Full text of "197612 Popular Electronics"

See other formats

14278

TV VIDEO GAMES FOR CHRISTMAS

Pnmilar Electronics

WORLDS LARGEST- SELLING ELECTRONICS MAGAZINE DECEMBER 1976 SI. 25

PE PROJECT FIRSTS!

Universal 4-Channel
Matrix Decoder

DECODES
OS

_ AND SQ

nrrnnniiiM

AND BROADCASTS- PLUS ' SURROUND
SOUND” WITH VAR 10 -MATRIX SYSTEM

A Solar Energy Meter

MEASURES SUN’S ENERGY

§>

Hobbyist Microcomputer

Build a Digital Auto
Gas Gauge

Propagation Delay-Logic -
Design Gremlin...and more

PLUS:

How to Determine
CD Radio

Communication Range

Annual Index of
1976 Articles
and Columns

TEST REPORTS:

Technics SA 5460
Stereo Receiver

Shure M24H
Stereo Cartridge

SBE Formula D “Touch-Corn”
AM CB Mobile

lx MIT

32xlr

DELTA

THE COBRA 32XLR.

A TECHNOLOGICAL PUNCHTHROUGH.

Cobra has a reputation for punching through
loud and clear. The new Cobra 32XLR, of course, con¬
tinues the reputation And creates another— for
innovative design, superb
engineering and technical
superiority.

Start with the illuminated
4-in-l meter. It tells you exactly how much
power you're pushing out and pulling in. As
well as monitoring your modulation in precise
percentages. And measuring your punch with an
SWR check. In short, the 32 XLR
lets you keep an eye on your ears.

ScanAlert, Cobra's unique scan¬
ning system, continually monitors
Channel 9 when you're on another
channel. If an emergency comes up, the ScanAlert
light goes on. And the incoming message automat¬
ically locks the receiver on the active channel.

For information on our complete line write for brochure #CB-2.

The 32XLR's Digital Channel
Selector is the very latest. With
large LED numerals — for a
read-out that registers clearly and
quickly. Plus switchable "pulse block" noise blank¬
ing' that rejects short-pulse noise not normally
blocked by other systems. Which makes it the most
effective in the business. Finally, add automatic noise
limiting, Dynamike Plus (with built-in power mike)
and Delta Tuning.

The new Cobra 32XLR. It has virtually every¬
thing. And it has everything to do just one thing.

Punches through loud and clear.

Cobra Communications Products
D YNASCAN CORPORATION
6460 W Cortland St., Chicago, Illinois 60635

CIRCLE NO. 17 ON FREE INFORMATION CARD

ttnctir m.

Discwasher Group
Columbia, Missouri

Measuring just 11" wide x 11" deep x 5" high, and weighing a
mere 7 pounds, the Altair™ 680b is a complete, general-purpose
computer.

The secret to this revolutionary ; small computer is its CPU
board. This double-sided board fits along the bottom of the Altair
case and plugs directly into the front panel board. It contains
the new 6800 microprocessor, 1,024 bytes of RAM memory, a 256
byte PROM monitor, provisions for 768 bytes of additional PROM
or ROM, and a single Interface port with a Motorola ACIA serial
interface adapter which can be configured either RS-232 or TTY.
A five level Baudot interface option is also available.

The Altair 680b can be programmed from front panel switches,
or it can be interfaced to a video display terminal, or teletype¬
writer. Three additional circuit boards can be plugged inside the
Altair 680b for further memory and interface expansion. The first
of these boards is a 16K static RAM memory board.

Software already developed includes Altair 680 BASIC with
all the features of the 8K BASIC previously developed for the
Altair 8800. These include Boolean operators, the ability to read
or write a byte from any I/O port or memory location, multiple
statements per line, and the ability to interrupt program execution
and then continue after the examination of variable values. This
software takes only 6.8K bytes of memory space and a copy is
included free with the purchase of the Altair 680 16K memory
board.

Other software includes a resident two pass assembler. The
Altair 680b is also compatible with Motorola 6800 software.

The Altair 6 80b is ideal for hobbyists who want a powerful
computer system at an economic price. Altair 680b owners qualify

NOTE: Altair is a trademark of MITS, Inc.

for membership in the Altair Users Group, and like other Altair
owners, they receive a complimentary subscription to Computer
Notes and complete factory support.

PRICES:

Altair 680b kit with complete, easy-to-understand assembly man¬

ual, operator's manual, and programming manual .$466

Assembled Altair 680b . $625

Altair 680b Turnkey model kit 395

Expander Card 680MB (required to expand 680) $ 24

Altair 680BSM 16K static RAM board kit with 680 BASIC . $685

Altair 680 BASIC when purchased separately., . $200

Baudot option .$42

MAIL THIS COUPON TODAY

□ Enclosed is a check for S _

□ BankAmericard # _ or Master Charge # _

□ Altair 680b □ Kit □ Assembled □ Other (specify)
enclose $8 for postage and handling

□ Please send free information package.

NAME _

ADDRE55 _

CITY _ STATE & ZIP _

DuQDl§©

2450 Alamo SE/Albuquerque, NM 87106, 505-243-7821

Price, specifications subject to change. Please allow up to 60 days for delivery.

POPULAR ELECTRONICS

CIRCLE NO. 76 ON FREE INFORMATION CARD

DECEMBER 1976 VOLUME 10, NUMBER 6

Popular Electron ics8

FEATURE ARTICLES

WORLDS LARGEST - SELLING ELECTRONICS MAGAZINE

ROUNDUP OF TV ELECTRONIC GAMES . KrisCarrole 32

HOW TO PREDICT CB RADIO RANGE . jra s. Gerson 48

Antenna height, ERP, noise, and sensitivity influence communication range.

UNDERSTANDING ACTIVE FILTERS . 5 . Don Lancaster 69

LAMP CIRCUIT QUIZ . Robert P. Balin 99

CONSTRUCTION ARTICLES

BUILD A UNIVERSAL 4-CHANNEL MATRIX DECODER . Robert Colman & Toshiaki Okawa 37

Decodes SQ and QS or provides surround sound or concert hall ambience.

MEASURE THE SUN’S ENERGY WITH A SOLAR RADIOMETER . Warren Jochem 45

SPECIAL FOCUS ON DIGITAL ELECTRONICS

HOW TO SELECT A HOBBYIST MICROCOMPUTER . Stephen B. Gray 51

DIGIT PROBE . . . . . Leslie Solomon 56

BUILD A MINIATURE DIGITAL STOPWATCH . Wayne Kashinsky 57

DIGITAL FUEL GAUGE . . . Gregory Baxes 59

AN A/D TEMPERATURE CONVERTER . W. J. Prudhomme 62

PROPAGATION DELAY— THE LOGIC GREMLIN . Ralph Tenny 64

COLUMNS

STEREO SCENE - 1 - - Ralph Hodges 24

Evaluating Four-Channel.

HOBBY SCENE Q & A . John McVeigh 28

INSIDE BASIC ELECTRONICS . Sol D. Prensky 86

Capacitors and RC Circuits, Part 2.

SOLID STATE . . . . . . Lou Gamer 90

T is the Season to be Solid.

CB SCENE . . . . . . . . Ray Newhall 94

More on Mobile Antennas.

COMPUTER BITS . Stephen B. Gray 1 01

Books on Programming

EXPERIMENTER’S CORNER . Forrest M. Mims 1 1 1

The Neon Glow Lamp.

PRODUCT TEST REPORTS

TECHNICS MODEL SA-5460 STEREO RECEIVER . 74

SHURE MODEL M24H ALL-FORMAT PHONO CARTRIDGE . 76

SBE MODEL 32CB FORMULA D TOUCH/COM CB TRANSCEIVER . 78

SENCORE MODEL TF70 PORTABLE TRANSISTOR TESTER . 79

DEPARTMENTS

EDITORIAL . . . . . Art Salsberg 4

Turning the Electronics Comer.

LETTERS . 8

OUT OF TUNE . 8

"Build the Ultimate Metronome " (July 1976)

"Power-Failure Alarm" (June 1976)

NEW PRODUCTS . 12

NEW LITERATURE . 22

NEWS HIGHLIGHTS . 30

ELECTRONICS LIBRARY . 109

OPERATION ASSIST . - . 1 1 0

EDITORIAL INDEX TO VOLUMES 9 AND 10 (1976) . . 1 1 4

ADVERTISERS INDEX . 135

POPULAR ELECTRONICS, December 1976, Volume 10. Number 6. Pub¬
lished monthly at One Park Avenue. New York. NY 10016. One year subscrip¬
tion rate for U.S., $9.98; U.S. Possessions and Canada. $12.98; all other coun¬
tries, $14.98 (cash orders only, payable in U.S. currency). Second Class post¬
age paid at New York, NY and at additional mailing offices. Authorized as sec¬
ond dass mail by the Post Office Department, Ottawa, Canada, and for pay¬
ment of postage in cash.

POPULAR ELECTRONICS induding ELECTRONICS WORLD, Trade Mark
Registered. Indexed in the Reader's Guide to Periodical Literature.

Ziff-Davis also publishes Boating, Car and Driver, Cyde, Flying, Modern
Bride, Popular Photography, Skiing and Stereo Review.

DECEMBER 1976

Material in this publication may not be reproduced in any form without per¬
mission. Requests for permission should be directed to Jerry Schneider, Rights
and Permissions, Ziff-Davis Publishing Co., One Park Ave., New York, NY
10016.

Editorial correspondence: POPULAR ELECTRONICS, 1 Park Ave., New
Yorit, NY 10016. Editorial contributions must be accompanied by return post¬
age and will be handled with reasonable care; however, publisher assumes no
responsibility for return or safety of manuscripts, artworic, or models.

Forms 3579 and all subscription correspondence: POPULAR ELEC¬
TRONICS, Circulation Dept., P.O. Box 2774, Boulder, CO 80302. Please allow
at least eight weeks for change of address, indude your old address, endos-
ing, if possible, an address label from a recent issue.

Popular Electronics9

EDGAR W. HOPPER

Publisher

ARTHUR P. SALSBERG

Editorial Director

LESLIE SOLOMON

Technical Editor

JOHN R. RIGGS

Managing Editor

STEPHEN B. GRAY

Senior Editor

Editorial

TURNING THE ELECTRONICS CORNER

ALEXANDER W. BURAWA

feature Editor

EDWARD I. BUXBAUM

Art Director

JOHN McVEIGH

Associate Editor

ANDRE DUZANT

Technical Illustrator

PATRICIA GIRRIER'BROWN

Production Editor

Contributing Editors

HAL CHAMBERLAIN, LOU GARNER
GLENN HAUSER, JULIAN HIRSCH
RALPH HODGES, ART MARGOLIS
FORREST MIMS, RAY NEWHALL
SOL PRENSKY, WILFRED SCHERER

JOSEPH E. HALLORAN

AJterfising Director

JOHN J. CORTON

Advertising Sales

LINDA BLUM

Advertising Service Manager

PEGI McENEANEY

Executive Assistant

STANLEY NEUFELD

Associate Publisher

ZIFF-DAVIS PUBLISHING COMPANY
Popular Electronics
Editorial and Executive Offices
One Park Avenue New York, New York 10016
212-725-3500

Hershel B. Sarbin. President
Furman Hebb, Executive Vice President
John R. Emery, Senior Vice President, Finance and
Treasurer

Phillip T. Heffernan, Senior Vice President, Marketing
Edward D. Muhlfeld, Senior Vice President, Sports Division
Philip Sine, Senior Vice President
Frank Pomerantz, Vice President, Creative Services
Arthur W. Butzow, Vice President, Production
Lawrence Sporn, Vice President. Circulation
George Morrissey, Vice President
Sydney H. Rogers, Vice President
Sidney Holtz, Vice President
Al Traina, Vice President
Philip Korsant, Vice President
Paul H. Chook, Vice President, Market Planning
Charles B. Seton, Secretary
Edgar W, Hopper, Vice President, Electronics Div.
William Ziff, Chairman
W. Bradford Briggs, Vice Chairman

Midwestern Office

The Pattis Group, 4761 West Touhy Ave.,
Lincolnwood, Illinois 60644, 312 679-1100
GERALD E. WOLFE, THOMAS HOCKNEY
Western Office

9025 Wilshire Boulevard, Beverly Hills. CA 90211
213 273-8050; BRadshaw 2-1161
Western Advertising Manager, BUD DEAN

Japan; James Yagi

Oji Palace Aoyama; 6-25, Minami Aoyama
6 Chome, Minato-Ku, Tokyo 407-1930/6821,
582-2851

The publisher has no knowledge of any proprietary
rights which will be violated by the making or using of any
items disclosed in this issue.

The year 1976 has been a good one for persons deeply interested in electronics.

I think the future might be even better— we are sitting smack in the middle of the
electronics revolution that was promised a few decades ago.

As we turn the comer to 1 977, we can see more clearly the fruition of many
research and development projects of the past. Just think. Electronic digital
watches were virtually unknown in 1 972. In 1 973 they cost a few hundred dollars
when, around Christmas, PE introduced a kit for less than $70. They’re expected
to sell for less than $20 in 1 977. Similarly, microcomputers were at the $3000 level
in 1 974 when PE published plans for a kit that sold for less than $400.

There are other examples we could mention, but the important thing is that the
imaginations of voracious consumers were captured by these enticing electronic
products. This led manufacturers to increase their production levels of medium-
and large-scale IC’s, thereby lowering their costs. As a consequence, product
sales increased further, and the cycle of decreasing costs continued — to the
benefit of the public.

Integrated circuits are making a host of products “smart.” Just watch things
happen in 77. For example, TV electronic games will be booming, thanks to
inexpensive dedicated microprocessors. It’s predicted that this consumer product
area will reach annual sales of 12-million units by 1980. New educational and
programmable calculators will bow in 77, taking advantage of lower-cost memory
chips.

In another area, the use of home TV receivers as video terminals will become
more apparent to many people in the new year. For example, the video disc is
promised in ’77, and Japanese manufacturers are revving up for production of
video tape cassette units (with a battle looming between JVC’s and Sony’s
systems). A video jack, promised by some manufacturers, will lower cost of
attachments. Hobbyist computer buffs already know that graphic display has come
of age right now.

There are also modifications on the audio front that could well change the
product mix in the future. These include the new Elcaset system that bridges the
gap between present-day cassettes and open-reel tape. Then there are
40-channel CB transceivers.

It is anticipated that all major areas of consumer electronics will exhibit greater
growth in the coming year. Of special interest is a market study by Venture
Development Corp. of Wellesley, Mass., which predicts that the hobby computer
market will show a 1 50 percent sales increase from 1 975 (just under 7500 units,) to
1 976 (over 1 8,600 units). The study also indicates that this “promises to be nothing
less than the leading edge of a consumer computer revolution.”

At this time of year, many people dream about some special “breakthrough.” I’m
no exception. One of my wishes is for the acknowledgement from outer space of
the hydrogen atom’s 1420-MHz frequency that earthlings have transmitted to outer
space in a search for extraterrestrial life. The odds are almost insurmountable
against making such a radio contact, of course. But just think of the excitement it
would generate — and the projects we could all build and use. After all, one never
knows what’s around the electronics corner.

Pest OTisfjes for a Jopous poltto Reason
anb a pappp J^eto Bear

POPULAR ELECTRONICS

oil the be/t to you

Look at ’em. Aren’t they pretty? But, their real beauty is the way they’ll turn your CB on!
Because with a “Kriket®” external CB speaker, you can hear more clearly than you ever

thought possible. Who else makes a full line ... to accommodate your

every need? Isn’t it about time somebody did?

Give one to a friend you care about.

Priced from $1 4.95 to $24.95. IrSlfnfeC^'lt

Available at CB dealers everywhere! c.

Siais/ Kriket ® speakers

World Wide Headquarters
Acoustic Fiber Sound Systems, Inc.
7999 Knue Road, Suite 116
Indianapolis, Indiana 46250
(317) 842-0620

Exclusive Canadian Distributor
Persona Communications Ltd.
1149 Pioneer Road
Burlington, Ontario L7M 1N7
(416) 639-9070

All AFS ®/KR I KET® speakers are manufactured in the U.S.A. using American materials and craftsmen.
DECEMBER 1976 Copyright 1976 Acoustic Fiber Sound Systems, Inc.

Imagine a microcomputer

Imagine a microcomputer with all the design savvy, ruggedness, and sophistication of the best minicomputers.

Imagine a microcomputer supported by dozens of Interface, memory, and processor option boards. One that
can be Interfaced to an Indefinite number of peripheral devices Including dual floppy discs, CRT’s, line printers,
cassette recorders, video displays, paper tape readers, teleprinters, plotters, and custom devices.

Imagine a microcomputer supported by extensive software including Extended BASIC, Disk BASIC, DOS and
a complete library of business, developmental, and Industrial programs.

Imagine a microcomputer that will do everything a mini will do, only at a fraction of the cost.

You are Imagining the Altalr™ 8800b. The Altalr 8800b Is here today, and It may very well be the
mainframe of the 70’s.

The Altalr 8800b Is a second generation design of the most popular microcomputer In the field, the Altalr 8800.
Built around the 8800A microprocessor, the Altalr 8800b Is an open ended machine that Is compatible with all
Altalr 8800 hardware and software. It can be configured to match most any system need.

MITS’ plug-in compatible boards for the Altalr 8600b now Include: 4K static memory, 4K dynamic memory,

16K static memory, multi-port serial Interface, multi-port parallel Interface, audio cassette record Interface,
vectored Interrupt, real time clock, PROM board, multiplexer, A/D convertor, extender card, disc controller,
and line printer Interface.

MITS’ peripherals for the Altalr 8800b Include the Altalr Floppy Disc, Altalr Line Printer, teletypewriters, and
the soon-to-be-announced Altalr CRT terminal.

Introductory prices for the Altalr 8800b are $840 for a kit with complete assembly Instructions, and $1100 for
an assembled unit. Complete documentation, membership Into the Altalr Users Club, subscription to “Computer
Notes*,’ access to the Altalr Software Library, and a copy of Charles J. Slppl’s Microcomputer Dictionary are
Included. BankAmerlcard or Master Charge accepted for mall order sales. Include $8 for postage and handling.

Shouldn’t you know more about the Altalr 8800b? Send for our free Altalr Information Package, or contact
one of our many retail Altalr Computer Centers.

mits 2450 ALAMO S.E. ALBUQUERQUE. NEW MEXICO 87106 (505)243-7821

Redesigned front panel. Totally synchro¬
nous logic design. Same switch and LED
arrangement as original Altair 8800. New
back-lit Dura I ith (laminated plastic and
mylar, bonded to aluminum) dress panel
with multi-color graphics. New longer,
flat toggle switches. Five new functions
stored on front panel PROM including:
DISPLAY ACCUMULATOR (displays con¬
tents of accumulator), LOAD ACCUMU¬
LATOR (loads contents of the 8 data
switches (A7-AO) into accumulator), OUT¬
PUT ACCUMULATOR (Outputs contents
of accumulator to I/O device addressed
by the upper 8 address switches), INPUT
ACCUMULATOR (inputs to the accumu¬
lator from the I/O device), and SLOW
(causes program execution at a rate of
about 5 cycles per second— for program
debugging).

Two, 34 conductor ribbon cable assem
blies. Connects front panel board to front
panel interface board. Eliminates need
for complicated front panel/bus wiring.

New CPU board with 808 OA micro¬
processor and Intel 8224 clock generator
and 8216 bus drivers. Clock pulse widths
and phasing as well as frequency are
crystal controlled. Compatible with a\\
current Altair 8800 software and
hardware.

altair 8800-b

2450 Alamo SE/ Albuquerque, NM 87106/505-243-7821

Pnces. delivery and specifications subject to change.

NOTE: Altair is a trademark of MITS, tnc.

CIRCLE NO. 49 ON FREE INFORMATION CARO

tow ollen
cooil you ose

OD Xcelite

it’s every
tool you
need 99 %
of the time...
an Xcelite original!

it's a screwdriver

...for slotted, Phillips , Frearson, Bristol,
dutch head, Scru/ox * screws; in inch
and metric size Alien hex and Allen hex
ballpoint socket types; and Pozidriv ®
style.

it's a nutdriver

...in inch and metric
sizes, regular, stubby,
and magnetic, for hex nuts, screws,
and bolts.

it's a reamer
it's extendable

€

...for greater reach and torque.

5 DIFFERENT HANDLE STYLES

...regular and Tee, with and without
reversible ratchet; junior, and stubby;
all with Xcelite’s unique spring device
for quick blade insertion and removal.

All shockproof, breakproof (UL).

85 INTERCHANGEABLE BLADES

...all the popular types and sizes. All
precision-made, genuine Xcelite qual¬
ity. Fit all five handles.

IN SETS, KITS,

OR PIECEMEAL

...roll-up service kits,
compact, stand-up,
plastic-cased sets; or
individually as needed.

in stock at leading
electronic distributors . . . nationwide

Weller-Xcelite
. Electronics Division
The Cooper Group w

P. O. BOX 728,

APEX, NORTH CAROLINA27502
CIRCLE NO. 71 ON FREE INFORMATION CARD

Letters

1-MHZ COUNTER 1C SOURCE

The 1 4583 Schmitt trigger 1C used in the
“Low-Cost 1-MHz Frequency Counter” (Au¬
gust 1976) is a Motorola part. It can be ob¬
tained from any large OEM dealer that distrib¬
utes Motorola parts or for $1.69 plus 25g
postage from the following address.— A/or-
man Huffnagle, 7511 Village Green Dr., Or¬
lando, FL 32807.

DIGITAL SPEEDOMETER COMMENTS

In the article “Build a Digital Speedometer
For Your Car" (September 1976), the open¬
ing states that the speedometer cable turns
1000 revolutions per mile travelled. If the
speedometer cable is connected directly to
the wheel, this means that the wheel must
make 1 000 revs per mile. The average radius
of a wheel is about 13", which means that its
circumference is 81.86". There are 63,360" in
a mile (5280 x 12). If we divide 63,360" by
81.68", we obtain 775.7 revs per mile. To
have 1000 revs per mile, the diameter of the
tire would have to be 20".— Edward J. Picar-
di, Philadelphia, PA

The speedometer cable is not connected to
the wheels. It goes to the transmission
through a gearing system . Most cars use
1000 revs per mile , although this may differ
from one make to another. We assumed
1000 revs per mile, but we also stated in the
paragraph on adjustment that you can make
the timing adjustment on a measured mile.

In reading the Speedometer article, I
happened upon several design errors. First,
IC2 through IC7 are TTL devices that operate
only between 0° and 70°C, which means that
during the winter months the speedometer
will have to be warmed up before it will oper¬
ate. Secondly, IC10 regulates the supply volt¬
age between 4.70 and 5.30 volts, while the
7400 series IC’s require voltage regulation
between 4.75 and 5.25 volts. — Kevin J. Byer,
Sr., Johnstown, PA

TTL devices do not freeze and will operate
below 0°C. The barrier voltage increases
somewhat with temperature reduction, but
the IC’s will operate where a human being
can tolerate the temperature. The operating
voltage range for TTL devices is from about
4. 7 to 5.3 volts. The output of the 309 regula¬
tor can range from 4.8 to 5.2 volts, with a typi¬
cal of 5.05 volts. Once the system is turned
on, power dissipation inside the 7400 IC’s will
heat up the chips; hence, there will not be
much of a "warm-up" time. Of course, if you
prefer better lower temperature devices, you

can use the 5400 series IC’s that operate
down to —55°C.

In the Speedometer article, you mention
two ways to make the final adjustment. How¬
ever, I feel that I have a way that is easier and
better. I connected a 4-digit tach to my car
and then started the engine and got it up to
the rpm l wanted for the mph I wanted to go. I
then made my final adjustment, using the for¬
mulas rpm = (mph x gr x 336)/td and mph
= (rpm x td)/(gr x 336), where gr is the gear
ratio of the rear end and td is tire diameter.—
Richard Perry, Everett, VA

We have not tried this one, but it looks like
it should work.

AN ELFIN TYPO

I have been very impressed by your careful
editing of the articles on building the COS-
MAC “Elf” (August and September 1976). I
found only one typographical error: In Part 2,
Fig. 1 shows a 4058 1C, whereas the text re¬
fers to a CD4508 and Fig. 2 shows 4508,s,
whereas the text refers to 4058’s.— - George
E. Smith, Homell Heights, Onatrio, Canada

The correct number in both cases is
CD4508.

HOME BREW CLARIFICATION

The article “Guide to Home Brew Phono
Preamp Design” (September 1976) is help¬
ful, but raises two questions. First, at the bot¬
tom of the first column on page 63, reference
is made to R6, RIO , and Rz in Fig. 5, which
does not have resistors with these designa¬
tions. Secondly, in the second column on
page 63, it is stated that tone controls can
easily be added to the Fig. 7 circuit. Where
should the controls go and what component
values should be used? — Carl Hartman ,
Newport Beach, CA

The 240-ohm, 100K, and 2.4K resistors
in Fig. 5 refer to R6, RIO, and Rz, respective¬
ly. The tone controls can be connected to the
output (wipers of the volume controls). To
prevent impedance problems , unity-gain op
amp buffers can be used with passive RC
networks. Or, active filters can be used.

“EXPERIMENTER’S CORNER”

I was just rereading parts of the June 1976
Popular Electronics and happened to
glance at the Experimenter's Corner. The
article on the TTL NAND gate is the most un¬
derstandable I have read in PE. — U. Vandrei,
Ontario, Canada

Out of Tune

In “Build the Ultimate Metronome" (July, p
57), R2 should go to pin 1 1 of IC2, not pin 10,
and R8 should go to pin 1 1 of ICS, not pin 1 0.

In “Power-Failure Alarm” (June, p. 55), Q2
is shown as an npn transistor, whereas the
2N2621 is a pnp device. Any general-pur¬
pose npn transistor will work.

POPULAR ELECTRONICS

All SBE

23-channel
CB units

have a

40-channel

With all the talk
about 40-channel
CB units tomorrow,
why should you
buy SBE 23-
channel units
today?
Simple. We just
give you the
chance to buy
today with to¬
morrow in mind.
Which is what the
SBE FUTURE-40 CB
UPDATE PROGRAM
is all about. Here's
how it works: We're
including a special
Future-40 Certifi¬
cate with all SBE
23-channel units.
It entitles the SBE
buyer to update
his 23-channel unit
to 40 channels

future.

A Future-40 CB Update Program Certificate comes packed in each of the following SBE units: Coronado II
(S8E-10CB). Cortez [SBE-21CB], Formula "D" (SBE-26CB), Catalina III (SBE-29CB), Touch, 'Com (SBE-32CB)
erute [SBE-34CB], Trinidad fSBE-HCBJ. Trinidad II (SBE-30CB). Sidebander II (SBE-12CB). Sidebander IV
(SBE-27CB). Console II (SBE-16CB). Console IV (SBE-28CB)

within 1977.

You send in the
certificate, we'll set
up the update of
your unit to a full
40 channels. All,
for a reasonable
charge, depending
on the model
involved.

Simple as that.

All in all, the SBE
Future-40 CB
Update Program is
aimed to hit those
people who'd like
to buy now, but are
a bit confused
about what's
around the corner.

And thinking
ahead, about
what's around the
comer, that's what
SBE is all about.

ISBEI

Batter Communications through Creativa Technology

For information write: SBE, Inc., 220 Airport Blvd., Watsonville. CA 95076
DECEMBER 1 976 INTERNATIONAL OFFICES: E.S. Gould Marketing Co. Ltd., Montreal. Canada/Linear Systems S.A. Geneva 1. Switzerland

CIRCLE NO. 55 ON FREE INFORMATION CARD

Hewlett-Packard Calculators:

The HP-91 scientific portable printing calculator
$425.00*

The HP-91 is a completely portable scientific calculator with
integrated printer. Now you can generate a permanent
record of each calculation to document your work, in the
office, or at a job site in the field.

♦ Lightweight briefcase portability. Operates on battery
power or AC.

♦ Full range of scientific and arithmetic functions complete
with printed record.

♦ Built-in, sophisticated, quiet thermal printer.

♦ Extra large, easy-to-read display.

♦ Four dozen built-in functions and data manipulation
Operations.

♦ Pre-programmed for science, mathematics and statistics.

♦ 16 addressable memories.

The HP-21 scientific
$80.00*

The HP-21 makes short work of
technical calculations. If you
seek a calculator that does more
than simple arithmetic, this is it.

♦ 3 2 built-in functions and

♦ Performs all standard log and trif
functions (in radians or degrees).

♦ Performs rectanguWpolar conversion,
register arithmetic and more.

♦ Addressable memory.

♦ Two selectable display modes: fixed point
and scientific.

♦ Lowest-priced HP scientific calculator.

The HP-22 business management
$125.00*

The HP-22 easily handles the kinds of
calculations most often faced in business
management today. It can breeze through
business math calculations and build existing
statistical data into reliable forecasts. If you want
a business management calculator, here it is.

♦ Combines financial, mathematical and statistical
capabilities.

♦ Performs complex time-value-of-money including
interest rates computations.

♦ Performs rates of return and discounted cash flows for
investment analysis.

♦ Performs extended percent calculations, accumulated
interest, amortization and more.

♦ 10 addressable memories.

♦ Full decimal display control.

The HP-27 scientific/plus
$175.00*

The HP-27 is for the scientist, engineer or business
person responsible for budgets, cost analysis,
resource allocations and more.

It features a comprehensive set of statistical and
financial functions for planning, forecasting and
analysis. For the first time, they’ve been added to
HP’s complete set of scientific functions.

♦ 10 financial functions for investment analysis.
NEW— internal rate of return and net present
value for uneven cash flows.

♦ 1 5 statistical functions for planning and forecasting.

♦ NEW -normal distribution and correlation
coefficients.

♦ 28 pre-programmed exponential, log and trig
functions for scientific and engineering calculations.

♦ 20 memories with selective clearing options for
greater flexibility, 10 of which are addressable
memories.

The First Family

The HP-25C scientific
with continuous memory
$200.00*

The HP-25C is our keystroke pro¬
grammable. It can solve automatically
the repetitive problems every scientist
and engineer faces. Whats more, its
Continuous Memory capability lets you
retain programs and data even when its
turned off.

♦ Continuous Memory capability.

♦ 7 2 built-in functions and operations.

♦ Keystroke programmability.

♦ Branching, conditional test and full
capability.

♦ 8 addressable memories.

♦ We also offer the HP-25 (without the
Continuous Memory feature) for $145.00*

The HP-97 & the HP-67 powerful fully programmable
calculators HP-97 $750.00* HP-67 $450.00*

The HP-97 and HP-67 are the most powerful fully program¬
mable battery-operated portable scientific calculators you can
buy. In fact, both offer about 3.4 times** the programming
power of our classic HP-65 - the industry standard. Programs
written for either the HP-67 or HP-97 can be run on the other
without modifications of any kind. The HP-97’s thermal printer
is also remarkable— and unusually quiet.

♦ Handles up to 224 steps.

♦ All prefix functions and operations are merged.

♦ Direcdy records programs or contents of all 26 data storage
registers onto magnetic cards.

♦ 10 user-definable keys.

♦ 3 types of addressing -Label, Relative and Indirect.

♦ 3 printing modes-Manual, Normal and Trace. (HP-97 only)

♦ Standard Application Pac with 15 program^of broad appeal
included free. Optional Pap§ in engineering, finance and other
disciplines availaJbleat$35.00 each.

**Complete details on request.

The HP-80 financial
$295.00*

The HP-80 performs calculations involving the relationship between time
and money: bond prices and yields, conversions, trendline analysis,
interest calculations and more. A built-in 200-year calendar figures
number of days in bond or loan calculations.

♦ Financial functions: simple interest, payment per period,
number of periods, present and future values, sum-of-the-
years^-digits depreciation.

♦ Bond functions: prices and yields, 200-year calendar.

♦ Statistical functions: mean, standard deviation, trend line.

♦ Mathematical functions: percentages, ^x*y,xserial or chain calculation!

♦ Addressable memory.

♦ Selectable display modes: fixed point and scientific notation.

•Suggested retail price —excluding applicable state and local taxes - Continental US. . Alaska and Hawaii.

Few mrtra information, on any of these
H«^ |fitT-Pac3taTd calculators and the name of
IJlrnearest dealer, simply telephone toll-free
30-648-47 II (in Nev. 323-2704 collect).

Or write: Hewlm-Packard, Dept.254E
1000 N.E. Circle Blvd,, Corvallis, Ore. 97330.

CIRCLE NO. 36 ON FREE INFORMATION CARD

HEWLETT hp PACKARD

Sales and service from 172 offices in 65 countries.
Dept-254E . 1000 N.E. Circle Blvd., Corvallis, Oregon 97330.

New Products

Additional information on new products
covered in this section is available from
the manufacturers. Either circle the itemys
code number on the Reader Service Card
inside the back cover or write to the man¬
ufacturer at the address given.

HY-GAIN REMOTE-CONTROL
MOBILE CB

The Hy-Gain 9 (Model 2679) is a 23-channel
AM, PLL-circuit unit with separate transceiver
and microphone/control. The microphone in¬

corporates digital channel readout, channel
selector, and volume and squelch controls. It
also acts as a loudspeaker. A coiled cable
links the control unit to an underdash connec¬
tor, from where a cable can be run to the re¬
motely located transceiver. Sensitivity is said
to be 0.7 fj.V for 10-dB (S+N)/N, adjacent
channel rejection at -40 dB, and full legal r-f
power output. The transceiver incorporates
automatic noise limiter circuitry.

CIRCLE NO. 88 ON FREE INFORMATION CARD

HITACHI RECEIVER

The SR-903 is Hitachi’s top AM/FM stereo
receiver, rated at 75 watts per channel with
less than 0.3% THD. The class-G amplifier

circuit is said to increase efficiency by at least
50%, thus eliminating the need for large heat
sinks and reducing the receiver’s weight by

almost 40 percent. Frequency response of
the FM section is 30 to 15,000 Hz ±1 dB, and
the FM tuner has a 1.6-microvolt sensitivity,
80-dB selectivity. A protection circuit shuts off
the speakers in case of an electrical malfunc¬
tion and lights an LED. Other features include
a 41-clickstop volume control, simultaneous
tape-dubbing and monitoring capability, high
and low filters, and afc that locks on to the
station when the user lets go of the tuning
knob. Measures 19WW x 15%"D x 55/s"H
(48.9 x 40 x 1 2.9 cm). $499.95.

CIRCLE NO. 89 ON FREE INFORMATION CARD

40-PIN 1C TEST CLIP

Continental Specialties has released the
fourth in its series of 1C test clips, the PC-40.
Patterned after the earlier models, the PC-40
is compatible with 0.6" center IC’s up to 40
pins. This mini-troubleshooter offers a narrow
throat for bringing 1C leads up from high-den¬
sity pc boards, thus minimizing accidental
shorts while testing live circuits. It can also be
used to inject signals and wire unused cir¬
cuits into other boards. Scope probes and
test leads lock onto gripping contact teeth,
freeing hands for other work. Noncorrosive
nickel/silver contacts provide simultaneous
wiping action and low-resistance connections
to 1C leads. Overall plastic construction elimi¬
nates springs and pivots. $13.75.

CIRCLE NO. 91 ON FREE INFORMATION CARD

AFS STEREO HUMP-MOUNT CONSOLE

The Kar Kriket KK-1080 is a hump-mount
console from Acoustic Fiber Sound Systems
that mounts a stereo radio, or an 8-track or
cassette system and has storage space for

four cartridges or seven cassettes. The con¬
sole requires no fastening devices, but rests
on the driveshaft hump. Polymer “teeth” in
the base prevent movement while driving. By
unplugging the power, antenna and remote-
speaker leads, the entire unit can be taken
out and placed in the trunk. Size is 12"D x
8"W x 7"H (30.5 x 1 9.3 x 1 7.8 cm). $9.95.

CIRCLE NO. 92 ON FREE INFORMATION CARD

CB SPEECH PROCESSOR

“Talk Power” is an add-on speech processor
from Communications Power, said to provide
a substantial increase in average speech talk

power for CB transceivers without spillover
and with minimum distortion. This logarithmic
speech compressor plugs into existing 4-con¬
ductor microphone receptacles, requires no
other CB-set connections or alterations. The
existing microphone is retained. A solderless
internal patch panel permits easy micro¬
phone connections. The unit operates from
vehicle battery or ac power line. Size is 4ys"W
x 3'A"D x 2%"H (1 2.4 x 8.2 x 6.7 cm). $69.95.

CIRCLE NO. 93 ON FREE INFORMATION CARD

PICKERING PHONO CARTRIDGE

“Stereohedron” is the name Pickering gives
to the new stylus-tip shape featured in the
XSV/3000 stereo cartridge. It is said to in¬

crease the area of contact with the groove
wall, and to increase record life because
force is spread over this greater contact area.
Specifications are: frequency range of 10 to
30,000 Hz; channel separation, 35 dB (refer¬
ence 1000 Hz), output, 5 mV; resultant track¬
ing force, 1 gram +V£, -Va (add 1 gram to
setting with record-cleaning brush). $99.95.

CIRCLE NO. 94 ON FREE INFORMATION CARD

PAIA POLYPHONIC KEYBOARD

The latest electronic music kit from PAIA is
OZ, a polyphonic pitch source for use as a
portable practice keyboard, mini-organ, or
trigger/pitch source for a synthesizer. The

unit is battery-powered and has a built-in
one-watt audio amplifier and speaker. A five-
position range switch transposes the 1 Vz-
octave keyboard for over 6W octaves of total
range. The switch-selectable step or multiple-
pulse trigger allows a simple synthesizer in¬
terface, and a mixing input permits playing
other instruments through the OZ amplifier. A
tone control rolls off the normal square-wave

POPULAR ELECTRONICS

If you thought a rugged,
professional yet affordable
computer didn’t exist.

think

1MSA1

8080.

Sure there are other commercial,
high-quality computers that can
perform like the 8080. But their
prices are 5 times as high. There is
a rugged, reliable, industrial com¬
puter, with high commercial-type
performance. The IMSA1 8080.
Fully assembled, it’s $931.
Unassembled, it’s $599. And ours
is available now.

In our case, you can tell
a computer by its cabinet. The
IMSAI 8080 is made for commer¬
cial users. And it looks it. Inside
and out! The cabinet is attractive,
heavy-gauge aluminum. The
heavy-duty lucite front panel has
an extra 8 program controlled
LED’s. It plugs directly into the
Mother Board without a wire
harness. And rugged commercial
grade paddle switches that are
backed up by reliable debouncing
circuits. But higher aesthetics on
the outside is only the beginning.
The guts of the IMSAI 8080 is
where its true beauty lies.

The 8080 is optionally
expandable to a substantial system
with 22 card slots in a single
printed circuit board. And the
durable card cage is made of
commercial-grade anodized
aluminum.

The IMSAI 8080 power

supply produces a true 28 amp
current, enough to power a full
system.

You can expand to a
powerful system with 64K of
memory, plus a floppy disk con¬
troller, with its own on-board
8080- and a DOS. A floppy disk
drive, an audio tape cassette input
device, a printer, plus a video
terminal and a teleprinter. These
peripherals will function with an
8-level priority interrupt system.
IMSAI BASIC software is avail¬
able in 4K, that you can get in
PROM. And a new $139 4K
RAM board with software

memory protect. For the ultimate
in flexibility, you can design the
system for low-cost multiprocessor,
shared memory capability.

Find out more about the
computer you thought didn’t
exist. Get a complete illustrated
brochure describing the IMSAI
8080, options, peripherals, soft¬
ware, prices and specifications.
Send one dollar to cover handling.

Call us for the name of the
IMSAI dealer nearest you.

Dealer inquiries invited.

IMS Associates, Inc.

14860 Wicks Boulevard

San Leandro, C A 94577 pe-12

(415) 483-2093

DECEMBER 1976

Another Heathklt Color TV breakthrough...

There’s never been e color n system like mis before.

A Bold New Concept In TV

The new GR-2001 TV system is the most
sophisticated, best performing color TV
kit we’ve ever designed, but it is also much
more. It is the heart of a total home view¬
ing system — a Computer TV!

Complete Programming Capability

With its optional Programmer, this Com¬
puter TV system allows you to program
your set for an entire evening’s viewing.
The top bank of 8 keys 00 accesses the
static NMOS RAM and turns the on-screen
clock display into a computer CRT read¬
out which allows you to see your “pro¬
gram” as you enter it through the bank of
12 keys below the programmer panel. The
selected time appears in the first four
digits of the clock display, the channel
number appears in the last two. First, en¬
ter the time at which you want the set to
change channels. Next, enter the channel
number you want. Then the memory takes
over. While you sit back and relax, the
Programmer automatically changes to the
right channel at the right time. You can
program up to 32 channel changes within
two 12/24-hour periods!

Those two programming periods add
extra versatility. Program the first for your
daytime viewing schedule, the second for
evening shows. Or, program the first for
week nights, the second for weekends.
You can even preselect the programs
young children can watch — once the pro¬
grammer is engaged, the manual key¬
board is disconnected and can only be
reactivated by the remote control or by
pressing the correct button on the pro¬
gramming panel.

You can even program the set to return to
manual operation at a preselected time,
then resume automatic operation at an¬
other time. When the last program you
want to see is over, the set can be pro¬
grammed to switch to an empty channel.
This will cause the screen to go blank and
the on-screen readout to flash on and off
indicating that it is time to turn the system
off with the front panel pushbutton or op¬
tional remote control.

Convenient Remote Control

The optional wireless remote control 0
lets you adjust volume, turn the set on or
off, adjust tint, activate the digital read¬
out, scan up or down through the pre¬
selected channels, and turn the optional
programmer on and off — all at the touch
of a button. This wireless remote control
has improved circuitry for greater range
and reliability and is the best we've ever
offered.

Random Access Tuning

The 3x4 keyboard [3] lets you instantly
choose any of up to 16 preselected sta¬
tions— up to 24 with the optional eight
channel accessory. Switch from VHF to
UHF, up or down, in any sequence, and
be tuned in instantly without switching
through empty channels. Up and down

buttons on the keyboard also let you scan
all the preselected stations.

Automatic Antenna Rotor Control

A Heathkit exclusive! With the optional
antenna rotor control 0], you can program
the GR-2001 to automatically rotate your
outdoor antenna system as it changes
from one channel to another, for optimum
reception on every channel. No special
knobs to turn, no buttons to push. You
can select up to eight separate antenna
headings with up to three stations per
heading. It’s perfect for areas where sta¬
tions are in widely separated locations.

Superb Color and Sound

The TV set itself contains dozens of cir¬
cuit refinements and improvements de¬
signed to give you the best picture and
performance you’ve ever seen. The Auto¬
matic Gain Control circuit, for example,
has been significantly improved to better
resist airplane flutter. And since you build
it yourself, you can be assured of a set
that is free of mass production “glitches”
that show up all too often in other sets
now on the market. Other improvements
are listed below.

Separate Audio IF Stage

The audio circuitry is probably the finest
on any commercial set in the world. The
sound signal has its own separate IF stage
0] to dramatically reduce the “buzz”
caused by the picture carrier modulating
the sound. You can hear the difference —
especially if you use the output jack to
connect the GR-2001 to your stereo sys¬
tem. The built-in wide-range speaker of¬
fers excellent fidelity as well. It’s one of
the first sets ever to give you real hi-fi
sound from a TV!

Phase-Locked-Loop Horizontal
and Vertical Hold Circuits

New phase-locked-loop horizontal and
vertical oscillators [e| “lock-in” on any
channel for a picture that’s rock-steady
and stable. There are no conventional ver¬
tical and horizontal hold controls because
you never need them! There are no align-

0 Programmer [3] Random-Access
Keyboard Tuning

ment problems either, so you get consist¬
ently excellent pictures year after year.

Black-Matrix Picture Tube

The GR-2001 ’s 25" (diagonal) ultra-rec¬
tangular picture tube 0 provides one of
the brightest, sharpest pictures in the
world. The tube is fully shielded to main¬
tain outstanding color purity by eliminat¬
ing stray magnetic fields.

Easy To Assemble

Though the GR-2001 is one of our more
complex kits, the average person shouldn’t
have any difficulty in assembling it. A
step-by-step illustrated manual will lead
you through assembly right up to trouble¬
shooting and testing. And if you do hap¬
pen to need assistance, help is only a
phone call away. A complete staff of
Technical Consultants will answer all your
questions. We won’t let you down.

GR-2001 Specifications

Deflection: Magnetic 90°.

Focus: Electrostatic.

Convergence: Magnetic.

Antenna Input Impedance: VHF: 300ft bal¬
anced or 75ft unbalanced. UHF: 300ft bal¬
anced.

Picture IF Carrier: 45.74 MHz.

Sound IF Carrier: 41.25 MHz.

Color IF Subcarrier; 42.17 MHz.

Sound IF Frequency: 4.5 MHz.

Video IF Bandwidth: 4.08 MHz at 6 dB
down.

Hi-Fi Output: Frequency Response: ±1
dB, 50 Hz to 15 kHz.

Output Voltage: Greater than 1.0 V RMS.
Audio Output: 4ft or 8ft, 2 Watts.

Power Requirement: 110 to 130 Volts AC,
60 Hz, 200 Watts.

Kit Net Weight: 146 lbs.

GR-2001 TV kit alone (chassis, picture
tube and one speaker): 699.95
Send for your FREE copy of our new cata¬
log containing almost 400 fun and practi¬
cal electronic kits.

Heath Company, Dept. 10-24
Benton Harbor, Michigan 49022

{5} Separate

Audio Circuitry

g] Horizontal ^ 0 Black-Matrix

and Vertical Picture Tube

Hold Circuits

displays the result instantly.

The NRI digital computer is one
of 1 0 kits you receive in the
NRI Complete Computer Elec¬
tronics Course. You build and
use your own TVOM, and
experiment with NRI's exclusive
Electronics Lab. You perform
hundreds of experiments, build¬
ing hundreds of circuits, learn¬
ing organization, operation,
trouble-shooting and program¬
ming.

NRI is the only
school to train you
at home on a real
digital computer.

Learn computer design, con¬
struction, maintenance and pro¬
gramming techniques on your
own programmable digital com¬
puter.

Qualified technicians are
urgently needed for careers in
the exciting new field of digital
and computer electronics . . .
and the best way to learn digi¬
tal logic and operations is now
available to you in NRI’s Com¬
plete Computer Electronics
Course.

This exclusive course trains you
at home on your own digital
computer! This is no begin¬
ner’s “logic trainer’’, but a
complete programmable digital
computer that contains a
memory and is fully automatic.
You build it yourself and use
it to define and flow-chart a
program, code your program,
store your program and data
in the memory bank. Press
the start button and the com¬
puter solves your problem and

New NRI Memory
Expansion Kit

The Model 832 NRI Digital Com¬
puter now comes with a new Mem¬
ory Expansion Kit. Installed and
checked out in 45 minutes, it dou¬
bles the size of the computer’s
memory, significantly increasing the
scope and depth of your knowl¬
edge of digital computers and pro¬
gramming. With the large-scale IC’s
you get the only home training in
machine language programming
. . . experience essential to trouble¬
shooting digital computers.

POPULAR ELECTRONICS

electronics at home.

NRI can train you at home to ser¬
vice Color TV equipment and
audio systems. You can choose
from 5 courses, starting with a
48-lesson basic course, up to a
Master Color TV /Audio Course,
complete with
designed-for-learning
25" diagonal solid state
color TV and a 4-
speaker SQ’“ Quadra¬
phonic Audio System.

NRI gives you both TV
and Audio servicing for hundreds
of dollars less than the two
courses as offered by another
home study school.

All courses are available with low
down payment and convenient
monthly payments. All courses

provide profes¬
sional tools and
‘'Power-On”
equipment along
with NRI kits
engineered for

training
With the
Master
Course,
for

instance,
you build
your own 5" wide-band
triggered sweep solid
state oscilloscope, digi¬
tal color TV pattern gen
erator, CMOS digital fre
quency counter, and
NRI electronics Discov¬
ery Lab.

NRI offers you five
TV/Audio Servicing
Courses

**Trademark of CBS Inc.

NRi’s Complete Communications Course
includes your own 400-channel
VHF transceiver

NRI’s Complete Communications
Course will train you at home for
one of the
thousands
of service
and mainte¬
nance jobs
opening in
CB; AM and
FM trans¬
mission and reception; TV broad¬
casting; microwave, teletype,
radar, mobile, aircraft, and marine
electronics. The complete pro¬
gram includes 48 lessons, 9 spe¬
cial reference texts, and 1 0 train¬
ing kits. Included are: your own
“designed-for-learning” 400-
channel VHF transceiver; elec¬
tronics Discovery Lab™; CMOS
digital frequency counter; and
more. You also get your all

important FCC Radio-telephone
License, or you get your money
back.

CB Specialist Course
also available

NRI also

offers a 37-lesson course in CB
Servicing with your own CB Transceiver, AC
power supply, and multimeter. Also included
are 8 reference texts and 14 coaching units
to make it easy to get your Commercial
Radiotelephone FCC License.

You pay less for NRI training and you
get more for your money.

NRI employs no salesmen, pays no com¬
missions. We pass the savings on to you
in reduced tuitions and extras in the way
of professional equipment, testing instru¬
ments, etc. You can pay more, but you
can’t get better training.

More than one million students have
enrolled with NRI in 62 years.

Mail the insert card and discover for your¬
self why NRI is the recognized leader in
home training. Do it today and get started
on that new career. No salesman will call.

If card is missing write:

NRI SCHOOLS
McGraw-Hill Continuing
Education Center
3939 Wisconsin Avenue
Washington, D.C. 20016

DECEMBER 1976

output to produce a more flute-like sound. Six
LED’s indicate range setting and trigger out¬
put. The pressure-sensitive pitch-blender
uses body capacitance to chromatically
transpose single notes or whole chords by up
to an octave for vibrato, glissando and trilling
effects. Size is 13"D x 11'Wx 4"H (33 x 27.9
x 10.2 cm). $84.95.

CIRCLE NO. 95 ON FREE INFORMATION CARD

OSI MAINFRAME COMPUTER

Ohio Scientific Instruments’ completely as¬
sembled mainframe computer, the OSI Chal¬
lenger, is designed to accept a number of op¬

tions. However, the minimum configuration
comes with a serial interface, 1 024 words of
RAM, and a 256-word monitor PROM, all of
which make the machine immediately usable.

Housed in a heavy-duty chassis, the comput¬
er has a UL-approved power supply with full
over-voltage and over-current protection. All
major IC’s are socketed. The backplane
board accepts eight OSI 400 system boards
for expansion purposes. Measures 17"W x
10"H x 12"D. $599.

CIRCLE NO. 96 ON FREE INFORMATION CARD

McClellan frequency counter

The pocket-sized 302 frequency counter from
the Gary McClellan Company has a frequency
range of 3 Hz to 20 MHz, better than 30 mV
sensitivity at 23 MHz, and ±0.005% accuracy.
Three frequency-measurement ranges and a
four-digit LED display combine to provide up
to seven digits of display. The 302 is powered
by a standard NiCd battery pack; the unit
comes with a charger. $120.00. Address:
Gary McClellan Co., P.O. Box 2085, 1001
West Imperial Highway, LaHabra, CA 90631 .

trolled motor. Feather-touch operation is pro¬
vided by a solenoid-operated logic-controlled
system that permits changing from one mode
to another without depressing the stop but¬
ton. Separate EQ and bias switches accom¬
modate three types of tape. Other features in¬
clude a memory rewind tape counter, line/
mic mixing, large VU meters, and MPX litter
switch. Under $700.

CIRCLE NO. 98 ON FREE INFORMATION CARO

EPICURE PREAMPLIFIER

The Epicure Four stereo preamplifier is rated
at less than 0.005% THD and -85 dB S/N for
the phono section (“C” weighted) and -100

SONY ELCASET TAPE DECK

The EL-5 is Sony’s front-loading tape deck
featuring the new Elcaset system that uses a
cassette shell larger than the Philips-type
cassette, with !4-inch tape travelling at 3 3A
ips. During automatic threading, the tape is
pulled out of the cassette for transport. The
EL-5 has two ferrite-and-ferrite heads, Dolby
noise-reduction system, and a dc servo-con-

wire-wrapping

center

•jj&i

jsr

Btyl

1 '-'yt r
\<£)

d/iiSI \
isryn ;

(T €

* i j

i r ?

1 m.

Cil |i

1- 1
i

; jg,.

; fl

1 W,|»

Isi

ill

wire wrapping
center

your one stop shopping for quality
electronic parts and tools.

50ft. wire
roll

dip

socket

pre~striped

wire

OK MACHINE & TOOL CORPORATION

3455 Conner St., Bronx, N.Y. 10475 / (212) 994-6600/ Telex 125091

CIRCLE NO. 46 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

Do-it-yourself JBL

Take the guts of what
makes JBL JBL and adapt
it to your own ideas of
what a loudspeaker system
should be.

Mix and match with forty-
seven individual JBL com¬
ponents— horns, lenses,
dividing networks, trans¬
ducers, everything.

•And when you’ve found
your perfect sound, we’ll
help you find somewhere
to put it: The JBL Enclosure
Construction Kit, with com¬
plete plans for building
your own loudspeaker en¬
closure from scratch.

See your authorized JBL
Loudspeaker Components
dealer for the start of a
great new team in sound:
You and JBL.

Gentlemen:

Send me your loudspeaker components
catalogue and the name and address of my
nearest dealer.

Name _

Address _

City -

State _ Zip _

Mail to: James B. Lansing Sound, Inc.

8500 Balboa Blvd.. Northridge. Ca. 91329

PE-12

James B. Lansing Sound, Inc. 8500 Balboa Blvd., Northridge, Ca. 91329

CIRCLE ND. 39 ON FREE INFORMATION CARO

Can another
portable DMM
measure up to
our popular
280?

You

&K-

&K-PRECISION
MODEL 280
$99.95

the judge!

?? 280

□ [7) Completely portable-

uses ordinary C cells or re-
chargeables.

□ [7) Measures AC/DC voltage,

AC/DC current and
resistance.

□ [21 High accuracy. DC accuracy

is ±0.5% on all but the
highest range (±1%). Ohms
accuracy is 1% on most ranges.

□ [7| Full measurement capability,

including current measure¬
ment to 1 amp.

□ 0 ImV, 1/iA, 0.1 H resolution.

□ [7| High/Low-power ohms

measurements.

□ [7] Large, bright LED display.

□ [7] Auto-polarity and decimal point.

□ [7] 10-megohm input impedance.

□ [7) 0° to +50° C operating range.

□ [7] Measures only 6.4 x 4.4 x 2".

Linder 2 lbs. with batteries.

□ [7| Full line of accessories including,

AC adapter/ battery charger,
tilt stand and carrying case.

Compare our features, accuracy
and price and you’ll see why thou¬
sands of buyers have selected the
B&K-PRECISION 280.

Now in stock at your local distributor.

PRODUCTS OF DYNASCAN

6460 West Cortland Avenue
Chicago, Illinois 60635 • 312/889-9087
l In Canada: Atlas Electronics, Toronto j

dB (“A” weighted). Frequency response is
said to be 20 to 20,000 Hz ±0.25 dB, high
level. Features two pairs of inputs for phono,
two pairs for tape, one pair each for tuner and
aux. Outputs are for two tape recorders and
two power amps. Controls are slide-type or
pushbutton. Other features include select¬
able inflection tone controls, front panel dub¬
bing and monitoring facilities, six ac power
outlets, muting relay with 10-second delay at
turn-on, steep-cutoff high and low filters, and
three regulated dc power supplies. Rated
output is 2.5 Vrms. Measures 1 8!4"W x 9^HD
x 5!4"H (46.4 x 24.1 x 14 cm). Comes with
rack mount or walnut panel ends. $449.

CIRCLE NO. 99 ON FREE INFORMATION CARD

PIONEER DIRECT-DRIVE TURNTABLE

Pioneer’s new high-end turntable, the
PL-530, is a dual-motor automatic direct-
drive model. The platter is driven by a brush¬

less dc servomotor, and the second motor is
used for fully automatic lead-in and return. A
double-float mounting system is said to be
unique and to absorb all external vibrations,
including feedback. Wow and flutter is rated
at 0.3% Wrms, and S/N at 70 dB (DIN B).
Other features include an S-shaped pipe
tonearm, viscous-damped cueing device,
strobe pattern on platter rim, and speed ad¬
justment of ±2%. Measures 1 8 29/32 "W x 1 5
1 1 /32"D x 6 1 1 /1 6"H (48 x 39 x 1 7 cm). $250.

CIRCLE NO. 100 ON FREE INFORMATION CARD

DYMEK ALL-WAVE OMNI ANTENNA

McKay Dymek's new DA 100 all-wave, om¬
nidirectional antenna is designed to replace
traditional outside long-wire antennas for im¬
proved reception in the 50-kHz-30-MHz
bands. Consisting of a 4-ft collapsible whip
attached to a small weatherproof box, the unit
contains a broadband untuned preamp. Out¬
put impedance is 50 ohms and is compatible
with any multi-band communications receiver
that will accept an external antenna. The
whip-amplifier section is mounted on a pole
or pipe, window frame, ledge, or any high
place. The control module, which operates
from the standard power line, can be placed
in any convenient indoor location. The control
module measures 9"W x 5"H x 9"D. Power re¬
quirement are 1 1 0 or 220 V ac (switch select¬
able), 50-60 Hz. $125.

CIRCLE NO. 101 ON FREE INFORMATION CARD

New Literature

PHONO CARTRIDGE DATA

A colorful six-page brochure which describes
the company’s “transversal suspension sys¬
tem” has been issued by AKG Acoustics on
five models of its “Phonocartridges.” Using
cutaway diagrams and line drawings, the bro¬
chure discusses the new system and pro¬
vides specifications on the five models in the
new line. Address: AKG Acoustics, 91 McKee
Drive, Mahwah, NJ 07430.

ELECTRONIC CIRCUIT-DESIGN AIDS

A 26-page catalog of electronic circuit-design
aids from sockets and breadboards to com¬
plete educational systems is available from
E&L Instruments. The catalog includes more
than 180 products for builders of electronic
circuitry. Described in the catalog are sys¬
tems for teaching and experimenting with op
amps, 1C logic, and microprocessors. Other
products covered are solderless breadboard¬
ing sockets, tools, component kits, and a se¬
lection of practical and instruction manuals.
Address: E&L Instruments, Inc., 61 First St.,
Derby, CN 0641 8.

IEEE STANDARDS CATALOG

The new 32-page catalog of IEEE Standards
lists over 350 standards publications in
numerical sequence and also provides a sub¬
ject index to the standards. Many American
National Standards published by the IEEE
are also included. Standards developed with¬
in the IEEE cover test methods, practices for
electrical installations, units, definitions,
graphic symbols, and application methods.
The catalog lists important new and newly re¬
vised publications on graphic symbols, metric
practice, and instrument interfaces. Address:
IEEE Standards Office, 345 E. 47th St., New
York, NY 10017.

DATA CONVERSION COMPONENTS

A 288-page 1976-77 Engineering Product
Handbook from Datel Systems contains infor¬
mation on A/D and D/A converters, sample-
holds, analog multiplexers, operational am¬
plifiers, power supplies, dc-dc converters, di¬
gital panel meters, digital panel printers, digi¬
tal panel instruments, and various data sys¬
tems. The data conversion components are
featured in three different technologies: mo¬
nolithic, hybrid, and modular. Address: Datel
Systems, Inc., 1020 Turnpike St., Canton,
MA 02021.

CIRCLE NO. 13 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

the realistic One-Hander

999s

NOW

ONLY

]4095

Everything’s in ONE Hand!

Volume/On-OH

Variable

squelch

LED

channel selector/
pilot light
Speaker/Mike

SAVE SO00

^Rugged handset
with pushbutton
mike, speaker,
channel selector,
on-off, volume and
^squelch

Red LED in
handset glows
when set is “On’
and lights the
channel number

C Coiled cord on
handset extends
to 5 — lets you
mount rest of
transceiver out
of sight

The One-Hander is a natural for mobile CB — and Radio
Shack invented it. Ride along with all the safety and
companionship CB offers — without ever having to fumble
around to make adjustments. (The 1 VzxSVaxJ" remote section
tucks away under dash, seat or in glovebox for theft
protection.) With all crystals for 23-channel coverage. Built-in
blanker and ANL chop out ignition-type noise. Ceramic filter
cuts station interference. Jack for optional-extra speaker.
Adjustable mounting bracket and power cable for any 12VDC
pos./neg. gnd. vehicle included. Buy during December —
save enough to pay for your (Archer®) antenna!

O DEE NEW 1977
' MLL- CATALOG

• Exciting New 56th
Anniversary Edition

• Over 2000 Exclusive
Products

• Full Color • 164 Pages
AT OUR 4200 USA STORES AND DEALERS

The TRC-55 base/mobile unit is packed with convenience
and performance features. Whether you use it for personal
2-way communications or for business, you'll appreciate the
all-pro design. Crystals for all 23 channels. SWR and S/RF
meters. Delta fine-tuning for bringing in off-frequency
stations. Adjustable RF gain and an IF filter optimize both
weak and strong signals. Digital timer/alarm clock turns on
the rig at any preset time. Add an external speaker and it’s a
public address system, too. On-the-air and modulation lights.
With plug-in mike, mobile mounting bracket, AC and
DC power cords.

EVERYTHING IN QUALITY CB SINCE 1960

Radio /hack

A TANDY COMPANY • FORT WORTH, TEXAS 76107
5000 LOCATIONS IN NINE COUNTRIES

* Retail price may vary at individual stores and dealers.

DECEMBER 1976

Stereo Scene

By Ralph Hodges

EVALUATING FOUR-CHANNEL

HAVE JUST spent the better part of a

weekend listening to and evaluating
four-channel records. Certainly it’s not
difficult to derive considerable satisfac¬
tion from many of these discs as musical
diversions. But when you’re called upon
to figure out exactly what’s going on,
spatially and directionally, then diversion
turns into work. And when faced with an
ambiguity in the sonic positioning of
some voice or instrument, it’s hard to
know whether to blame the recording,
the medium, the listening room, or your
own ears.

I have a sneaking suspicion that get¬
ting the most out of four-channel sound,
as the commercial record companies
are presenting it to us, will turn out to in¬
volve a gradual learning process. I know
that, over the years, IVe gotten better at
ferreting out the producer’s intent in the
“surround sound” type of recording, and
I don’t think superior decoders and re¬
cording techniques are entirely respon¬
sible.

For example, during my first months
of quadraphonic listening I could play a
surround-sound record three or four
times before realizing that the acoustic
guitar on band 3 was coming — or was
supposed to be coming — from the right
rear. With more practice, I began to find
that I could make such distinctions al¬
most instantly in many cases. In short, I
had apparently developed a sensitivity
to certain aural “cues,” and perhaps
even a certain ability to anticipate the
producer’s hand on the pan pot. This
was certainly a far cry from my first en¬
counters with four-channel, when I often
found myself standing in the middle of a
room, listening to a discrete “ambiance-
type” quadraphonic tape of a symphony
orchestra, and wondering which direc¬
tion was front.

Matrix Anyone? Of course, it is this
sort of ambiguity for which early matrix
systems have been notorious, even
though many discrete recordings have
not been entirely free of it either. Indeed,

it is easy to bad-mouth the matrix ap¬
proach; a little too easy in my opinion. If
a simple Dynaquad hookup can do so
much to enhance the experience of re¬
corded music, then a still-more-elabo¬
rate matrix must be good for something,
right?

Well, during this past weekend I finally
got around to assembling the equip¬
ment, acquiring the records, and doing
the listening necessary to make or break
the case for matrix in my own mind.

The Equipment. This project was
precipitated by the almost simultaneous
arrival of several key ingredients: CBS
SQ and Sansui QS-encoded versions of
Michael Oldfield’s recording Om-
madawn, the only strictly commercial re¬
lease I know of that is available in these
two systems; a freshly checked-out San¬
sui QSD-1 QS decoder: and a brand-
new SQL-200 SQ decoder from CBS
Technology Center.

Both of these decoders are logic-
assisted in their own proprietary ways.
The Sansui is the most elaborate of the
Vario-Matrix decoders, functioning in
three separate frequency bands in an ef¬
fort to provide maximum aural separa¬
tion. The CBS product combines the
gain-riding “corner” logic with the re¬
cently developed variable-blend tech¬
nique to enhance front-to-back separa¬
tion.

With a left-front input, the frequency
response of the Sansui measured up al¬
most 2 dB in the mid-bass region, down

about XA dB in the upper mid-range, and
down at least as much above 14 kHz or
so. The CBS device was admirably flat
at low frequencies but rose almost a dB
in the upper mid-range, descending to
about -2 dB above about 9 kHz. These
measurements were made with the CBS
STR 130 test record by comparing a
straight-through signal with the re¬
sponse plots obtained when each of the
decoders was inserted into the chain*
And they were made after the comple¬
tion of listening to avoid prejudicing sub¬
jective reactions.

Ommadawn. This recording, which
served as the standard for comparison
of the two systems, was a reasonably
happy choice in one respect and a poor
one in another. Mr. Oldfield’s work is
nothing if not repetitious, and this per¬
mitted the same musical material to be
judged at length without constantly
backtracking on the record. This was
good. What was not so good was that
the two records — SQ and QS — were not
equivalent in quality. The QS version,
apparently cut and pressed in England,
tended to be noisy and distinctly “un¬
clean” sounding (for lack of a better term
to describe various distortions). The SQ
disc, a domestic product, was head and
shoulders above this mediocre level
(good on you, Columbia, for once!), and
the difference had to be allowed for in
the comparisons.

Nor was this the only difference. Once
I got going, with levels matched and
channels frequency-equalized with the
appropriate test records, it became clear
that I could have easily been dealing
with two separate mixes of the original
master tape. The SQ disc, on first hear¬
ing, exhibited much more evidence of in¬
tense rear-channel activity than the QS,
which seemed to sneak an instrument
behind you only occasionally.

In this respect, the SQ rendition was
more impressive and satisfying. But
trouble occurred in subsequent playings
when I tried to determine precisely what
was happening, and where, in the SQ

POPULAR ELECTRONICS

You're going to spend $300

fora receiver?

And you never heard of PPR?

Stereo

Receivers

Sugg. Ret.t
Price

Min. RMS Power

Per Channel into 8 Ohms

Total Harmonic
Distortion at
Rated Power (Max.)

FM Sensitivity

IHF *58 Stereo -50dB*

SA-576Q

$799.95

165 watts from 20Hz— 20kKz

0.03%

1.8*V

35.7dB1

SA-5560

499.95

65 watts from 20H2— 20kHz

0.1

1.8 /tV

36.2dBf

SA-5460

399.95

65 walls from 20Hz— 20kHz

0.1

t.fyzV

36.2dBf

SA-5360

299,95

38 watts from 2QHz-20kHz

0.3

1.9 mV

37.2dBf

SA-5160

229.95

25 watts from 3QHz-20kHz

0.5

1.9 /iV

37.2dBf

SA-506G

169.95

12 waits from 40Hz— 20kHz

0,9

2.0 aV

38,2dBf

TTechnics recommended price, but actual retail price will be set by dealers. *New IHF ’75 standard

PPR is price performance relationship. And we feel it's a meaningful way of judging a
receiver because it can tell you how much power, technology and performance youfre
getting for your money.

And when you look at our price performance relationship it's easy to see why
your next receiver should be a Technics.

Of course, we want you to listen to our receivers. Especially since all six have
the reserve power to float through complex musical passages with a minimum
of distortion and clipping. And they all have rugged transformers. Bridged
rectifiers. As well as high-capacitance filtering.

Play a record. You'll hear it the way it was recorded. Quietly
and with greater dynamic range. Because we use an overload-
resistant 3-stage 1C in the phono equalizer sections.

Tune in an FM station. Even a weak one. In addition to
hearing all the music, you'll also get increased stereo
separation. Negligible distortion. And a minimum of noise. j

Thanks to flat group delay filters and Phase Locked \

Loop IC's in the tuner sections. ^ ^

So if you'd like to know a simple way to discover
just some of the reasons why a Technics receiver —

is so good . . . it's as easy as PPR.

All cabinetry simulated wood.

Technics

by Panasonic

CIRCLE NO. 66 ON FREE INFORMATION- CARD

rear channels. Within the thick textures
of Oldfield’s orchestration it was next to
impossible. The sound certainly sur¬
rounded one in a flattering wash of aural
color; and, in the few spots where in¬
strumentation became simple, the locali¬
zation was reasonably good. However,
as a whole the impression was one of
vague zones of sonic identities. Fre¬
quently they seemed to shift, but I could
never be sure just where.

Sansui QSD-1 Synthesizer Decoder .

By contrast, in the QS rendition the lo¬
calization of sound sources was relative¬
ly precise, and most of it frontal. Now
and again an instrument would pop up in
the rear, and usually it would stay put.
What the QS cut lacked was the
“spacey” impression of the SQ render¬
ing, which was genuinely dramatic al¬
though imprecise and undefinable. (The
recording also lacked adequate treble,
which was a severe handicap in the
comparison.)

Logic, etc. As mentioned before, the
records seemed like products of two dif¬
ferent mixes, and quite possibly they
are. But if we can legitimately make the
assumption that both were intended to
be faithful to some prior “authoritative”
mix, and if we then ask which of the two
is the more faithful, I think the edge has
to go to QS. It was able to exhibit the
stability of localization that, in general,
enabled you to confirm where instru¬
ments were, and one would expect that
to have been a goal of the engineer who
created the four-channel mix. On the
other hand, every time I tried to focus in
on the specifics of SQ’s quadraphonic
image I became more confused rather
than less, despite the enjoyment I de¬
rived from the spacious-seeming SQ
“wash” of sound.

Both manufacturers are wont to give
highly impressive separation figures for
their logic-assisted decoders (ranging
from 20 dB to infinity), but these don’t re¬
flect the changing conditions encoun¬
tered in music. Ultimately, when all four
channels get equally busy, any logic ma¬
nipulation has to be turned off within the
decoder, and the system reverts to the
separation figures of the basic matrix (3
dB between adjacent channels). But

what happens as the condition of equal
busy-ness is approached? My guess is
that the SQ “corner” logic is turned off
first, because any attempt to keep its
gain-riding action going will result in a
loss of signal. The variable-blend should
be able to go on working forever, if
you’re willing to accept the loss of left-
right separation it imposes.

The QS Vario-Matrix system would
seem to have an advantage in being

able to keep its logic going almost up to
the bitter end. Its action involves no sig¬
nal losses, and the logic circuits can be
designed to function speedily and drasti¬
cally with no obvious distortions of the
aural image. As far as I can tell, neither
of these systems shines with material
like the steady-state drone of Om-
madawn , but the QS decoder holds on
to its localization deeper into the stew of
sound than the SQ unit, and the princi¬
ple of its logic operation is as good an
explanation for this as any.

Other Recordings. On the better am¬
bient-type four-channel recordings, I can
find virtually no fault with either of the
matrix systems. Evidently, one of the
fronts on which real progress has been
made in recent years is the miking and
mixing of credible ambiance and rever¬
beration. Even the highly touted new
Columbia recording of Carmina Burana
with Michael Tilson Thomas and the
Cleveland Orchestra, nominally a sur¬
round-sound or at least wrap-around-
sound production, has its (rather short¬
lived) moments in which the evocation of
large spaces is powerful. On the Vox la¬
bel, engineers Joanna Nickrenz and
Marc Aubort have captured some re¬
markably rich and spacious sounding
reverberation in QS-encoded form. A
particular standout is Ravel’s orchestral
works with the Minnesota Orchestra, al¬
though the disc processing does not al¬
ways do full justice to the inherent merits
of the recordings.

Every once in a while, someone
arises to deplore the fact that current
four-channel schemes have no specific
provision for a height dimension; these
remarks are often accompanied by a
proposal for ceiling speakers, or at least

units that are placed higher up the walls
than is customary. Nevertheless, if
memory serves, it was James Cunning¬
ham, an eminent name in audio for
many years, who first suggested that
conventional four-channel techniques
can produce a feeling of height, and
then proceeded to prove it with several
demonstrations. He has proved it again
on a record produced with his assis¬
tance on Dick Schory’s Ovation label.
The disc serves as a four-channel (QS)
demonstration vehicle and sampler for
the Ovation catalog. In my opinion, the
best moments come in the demo sec¬
tion. It Includes an all-too-brief excerpt
from a fabulous thunderstorm, a rousing
fireworks bombardment, and a few aptly
designed synthesizer effects.

The Cunningham/Schory thesis is
that a mono signal from all four speakers
will produce an apparent sound source
somewhere over a centrally located lis¬
tener’s head. The technique seems to
work fine. At one point there is an elec¬
tronic hailstorm of sound that appears to
rise up from the front speakers, pass
over the listener s head at a point some¬
where about ceiling level, and dive back
down into the rear speakers. Then there
is a brief sea-scape excerpt, where I
hear the cries of a gull hovering on a
thermal about 15 or 20 feet above the
surf. I may be kidding myself in some
way, but I swear that’s where the bird is
to my ears, with very little ambiguity.

I hope this means that four-channel is
making some progress. I confess to be¬
ing a fan of the medium — or its potential,
at least — and I certainly don’t want to be
the last on my block with four speakers
in his listening room. O

COMING UP IN
THE JANUARY

Popular Electronics'

Morse-to-Alphanumeric
Code Converter Project

Build a Low-Distortion
Audio Generator

Meters for Electronics
Test Reports:

JVC AM/FM Stereo Receiver
Sansui AM/FM Stereo Tuner
Kenwood Audio Amplifier

POPULAR ELECTRONICS

Yamaha headphones take the
headache out of holiday shopping.

Every year it’s the same old story. You move
heaven and earth trying to find a gift that’s both
personal and practical. After all, you never were
one to buy just any new thing and call it a gift. It’s
got to be right. No matter how long it takes to
find it.

So this year, give Yamaha HP-2 Ortho¬
dynamic headphones. They’re headache-proof.

For both the gift-giver and the gift-getter. There
are just two criteria. You must like someone. And
that someone must like music. Simple as that.

Just buy them and wrap ’em.

Mario Bellini to help us make these headphones
the most comfortable ever worn. A soft strap
distributes the HP-2’s featherlight 8 ounces evenly
over your head. The ear cups, with supple foam
pads, are specially designed to ride lightly on your
ears. Instead of flattening them out. And of course,
height and angle are completely adjustable.

In short, the HP- 2s add the convenience of
personal listening to the enjoyment of any stereo
system. They’re compatible with anything that’s got
a headphone jack. And make most anything
sound better, too.

Holiday cheer for the ear. Yamaha’s Ortho¬
dynamic design offers the crisp highs of the best
electrostatic headphones, and the rich, clean bass
of the best dynamic types. So all the music
comes through.

What’s more, the HP-2’s superb tonality,
wide frequency response and low distortion are
comparable to those of headphones costing much
more than our suggested retail price of $45. (In

other words, your gift sounds more like
a million dollars than a few dollars.)
And there’s comfort to match. Yamaha
consulted world-famous designer

NO. 67 ON FREE INFORMATION CARD

A gift that sits on the head instead of the
shelf. And, unlike some things you might give,
Yamaha headphones won’t wind up gathering dust
in the comer. They’ll be enjoyed. And used.

Chances are, they’ll spend part of each day on
someone’s head. And you’ll spend part of each day
on someone’s mind.

(Or, if you give to yourself, you’ll experience
the best of both worlds this holiday season. And,
why not? You don’t deserve any headaches either.)

Yamaha HP-2 Orthodynamic headphones.

Only at your Yamaha Audio Specialty
Dealer. Where you’ll find lots of terrific ways
to say “Happy Holidays’’

By John McVeigh

WIDEBAND NOISE GENERATOR

Q. /Ve heard that a “white” noise gen¬
erator is very usefui in checking out
shortwave receivers. I’d like to ex¬
periment with one , but don't have a
circuit Do you?

—Stu Goldberg, Cambridge, MA

A. The circuit shown will produce wide¬
band r-f noise. It uses a reverse-biased
diode and has a low-impedance output.
You can use it to align the receiver for
optimum performance.

+]_ 50K
~ 9 V

— B/Tlt -

iok J r!

IN2I

T — 7

I 50J1

I _

“ToOIjjF

LINE VOLTAGE MONITOR

Q. ifm not sure , but I think that the line
voltage of the commercial power
mains in my area varies a great deal.
Do you have a simple circuit for mo¬
nitoring the line? I have used my
VOM to do this , but I’d like to leave
something in the line continuously.

— Phil Poyner, Corpus Christi, TX

A. This circuit can be left in the line as a
continuous monitor. It will give reliable
indications over a limited range up to
about 125 volts. Use an accurate ac
voltmeter to calibrate the unit. An isola¬
tion transformer is included for safety
reasons. However, the circuit does not
draw much current, and a low-wattage
transformer can be used.

RADIO SPECTRUM ALLOCATIONS

Q. Do you know where l can find de¬
tailed information on radio frequency
allocations for the various services ? I
realize there will be revisions at the
outcome of WARCV9, but for now
any information would be appreciat¬
ed. — Richard Collins

A. A fairly complete listing of radio allo¬
cations in tabular form is found in Vol¬
ume II, Part Two of the FCC’s Rules and
Regulations. The listing is done by fre¬
quency from below 10kHz to above 275
GHz. Allocations are given under the fol¬

lowing categories: Worldwide: Region II
(the Americas); United States; and Fed¬
eral Communications Commission. For
details on getting a copy, write to the
Superintendent of Documents, U.S.
Government Printing Office, Washing¬
ton, DC 20402.

CRYSTALS

Q. I’m looking for miniature, low-fre¬
quency crystals for the 50- to 250-kHz
frequency range. Do you know where
I can find some?

— Sam Schwart, Nova Scotia

A. I would suggest that you contact the

International Crystal Manufacturing Co.,
Box 32497, Oklahoma City, OK 73132.
They have a very broad line of crystals
and oscillators for just about any fre¬
quency of interest to experimenters and
hobbyists. But I don’t know how small
they can make crystals that oscillate at
such low frequencies.

SURGE CURRENT PROTECTION
Q. My solid state power supply went
dead when I turned it on. There is
nothing wrong with the circuit f and all
components checked out okay be¬
fore I assembled the project. But the
rectifier went west. Any ideas?

—John Nagurney , Urbana, IL

A. Apparently the surge current flowing
through the rectifier was more than it
could handle. When you first turn on the
supply, the large filter capacitors are
essentially dead shorts until they start
charging up. This causes a surge cur¬
rent of many amperes to flow through
the diodes. Although you can replace
the rectifiers with ones having larger
surge current ratings, it’s best to either
insert some resistance in series with the
capacitors or to use a circuit like that
shown here. The power supply is turned

TO FILTER
CAPACITOR

on as slowly as the 2200-uF capacitor
charges through R1. The greater the re¬
sistance of R1, the longer the turn-on
time will be. Experiment with various val¬
ues until the delay is suitable for your
application. This circuit is especially ef¬
fective in eliminating the “thump'1 that
occurs in audio power amplifiers. The
transistor specified has a maximum col¬
lector current rating of 1 5 Amperes and
a total device dissipation of 115 watts. A
smaller transistor can be used in low-
power circuits.

Have a problem or question on circuitry, compo¬
nents, parts availability, etc? Send it to the Hobby
Scene Editor, popular electronics, One Park
Ave., New York, NY 10016. Though all letters can’t
be answered individually, those with wide interest
will be published.

POPULAR ELECTRONICS

THE LOGICAL CHOICE: Third in a series

SYMMETRICALAND
UNSYMMETRICAL PULSES
0.5Hz-5MHz.

CONTINUOUS, MANUAL
ONE-SHOT & EXTERNAL
TRIGGER OPERATION
External triggering to 10MHz

IN DEPEN DENTLY-
CONTROLLABLE PULSE
WIDTH & SPACING
100 nanosec-1 sec in 7 overlap*
ping ranges 107:1 duty cycle
range

INDEPENDENT CMOS AND
TTL OUTPUTS Fan-out to
40 TTL loads

SYNCHRONOUS OUTPUT
GATING

lOOmV-IOV POSITIVE
OUTPUT Less than 30
nanosec rise/fall times

CSC'S DESIGN-MATE 4: $124.95.
NO OTHHl DIGIIAL PULSE GBBtATOR
GIVES YOU SO MUCH, FOR SO LITTLE.

Sounds hard to believe ... but even a brief look
at Design-Mate 4’s specifications proves CSC's
engineers have done it again. Whatever your
application— whether you're looking for precision,
flexibility or just plain economy —this compact
source of fast, clean digital pulses offers the
performance you need . . .at a price that discourages
procrastination.

Use it as a clock source, delayed pulse
generator, synchronous clock, manual system
stepper, pulse stretcher, clock burst generator or
in dozens of other applications. Use it alone or in
tandem with other DM-4's for gated control. The

wide range of controls and multiple outputs give
you enormous versatility. . . plus compatibility with
all major logic families, for research, design,
development, quality control, production testing,
maintenance, troubleshooting . . .you name it.

Now, read the specs that follow. . . and check
the price again. Or better yet, try DM-4 for yourself
at your local CSC distributor. Once you do, we
think you’ll find it's as hard to do without as it is easy
to own.

For more information about CSC's other fine
products, and a list of distributors, please call or
write.

DM-4 SPECIFICATIONS

Frequency Range:
Pulse Width
and Spacing
Controls:

Duty Cycle:

Operating Modes:
RUN

TRIG

Input requirements:

GATE

Input requirements:

0 5 Hz to 5 MHz
100 nanosec to 1 sec in 7
overlapping decade ranges
A single-turn vernier control
provides continuous
adjustment between ranges.
10 -to 1 Range: adjustable
over entire pulse width/
spacing range. 1O0 nanosec
ON" 1 sec ' OFF to 1 sec
ON' and 100 nanosec OFF

0.5 HztoS MHz as per width/
spacing and amplitude
control settings
DC to approx 10 MHz
Sine waves 2 VP-P; pulses
1 V peak. >40 nanosec wide;
maximum input±10V (Input
Impedance: Approx. 10KHDC
coupled.)

Synchronous gating. Lead¬
ing edge of gate signal turns
generator ON Last pulse
is completed, even if gate
ends during pulse
Same as TRIG Mode

ONE-SHOT

OUTPUTS:
VAR OUT

Amplitude

Rise/fall

time

Impedance

TTL OUT

Fan-out

Sink

Rise/fall

time

SYNC OUT

Pulse width

Pulse lead
time

POWER

SIZE

(WxLxH)

WEIGHT

Pushbutton for single pulse
Output pulse occurs each
time push-button is pressed

0.1-10 V positive
Less than 30 nanosec

4O0Omax

40 TTL Loads

160 milliamps— 0 8 V max

Less than 20 nanosec

Approx. 40 nanosec Other
sync pulse spec s same as
TTL out.

Sync pulse leads outputs by
approx 20 nanosec.

117 VAC ±10%. 50/60 Hz. 5
watts (220 VAC. 50/60 Hz
also available, at slightly
higher cost )

7.5x6.5x3 25"

191 x 165 x 83 mm
2 lbs (0 91 Kg) _

APPROX 40 NANOSEC

►I N-

_□ _

JU¬

JU.

JU¬

JU-

JZ L

^ TV MIN

GATE

TTL OR VaR
OUT

1ST PULSE f I

COINCIDENT ^ J“| [~| n n n PI WST PULSE COMPLETED |

WITH LEAO EDGE
OF GATE SIGNAL

GATE

MODE

THRESHOLD

TRIG — * -

_□ _ \

ONE SHOT ■

PUSHSUTTON

l£l

OR VAR OUT-

ONE-

SHOT

MODE

CONTINENTAL SPECIALTIES CORPORATION

44 Kendall Street, Box 1942 New Haven, CT 06509 • 203-624-3103 TWX: 710-465-1227
West Coast office: Box 7809, San Francisco, CA 94119 • 415-421-8872 TWX: 910-372-7992

EASY DOES IT

DECEMBER 1976

CIRCLE NO. 18 ON FREE INFORMATION CARD

“10-Four, Good Buddy!”

CB Crossing the Border

The Canadian and Mexican governments have recently
been getting tough on incoming motorists with Citizens
Band radios. Unless you have a permit to use your radio
in either country, your set could be confiscated at the
border or sealed against use. To insure against this, send
a copy of your FCC license to any office of the Canadian
Dept, of Communications, at least six weeks before
your trip. Travelers bound for Mexico must write to the
Secretaria de Communicaciones, Mexico City, or con¬
tact the nearest Mexican consulate.

Marine Radiotelephone Misuse

A recent nationwide survey made by the Radio Techni¬
cal Commission for Marine Services has indicated a rap¬
idly growing increase in the misuse of marine radiotele¬
phone. Focusing primarily on vhf/FM, which is used by
more than 250,000 boatmen, the Commission observed
that there was unnecessary and excessive use of chan¬
nel 16 (the emergency channel), overly long conversa¬
tions, omitted callsigns, and excessive use of procedural
words. Unlike Citizens Band, which is intended for
business or personal use, the Marine Band is emergency
oriented. The commission praised the well disciplined
radio communication used by air traffic controllers,
where every word spoken is essential, in comparison to
many marine communications where exchanges are
long and cumbersome,

CMOS For Garage Openers

With the introduction of a new digital radio control by
Chamberlain Manufacturing, in its “Electro-Lift” gar¬
age-door openers, the possibility of outside false activa¬
tion of automatic garage-door openers has been nar¬
rowed. New CMOS integrated circuits built into the ra¬
dio’s transmitter and receiver allow homeowners to se¬
lect their own exclusive codes. The control, called
‘‘Code Command,” provides up to 64 possible code
combinations for added security.

Electronic Organ Tuning Advance

A new digital IC tone-generator system introduced by
Schober abolishes any need for organ tuning adjust¬
ments. The new circuitry uses digital logic technology to
make pitch relationships among the notes of an organ
permanently correct. An oscillating circuit generating a
signal about 250 times as high as the pitch of the highest
organ note acts as a reference source for all the pitches.
A single knob on the front of the organ alters the tuning
so that pitch can be adjusted to match a recording or the
tuning of another instrument. Before the development
of this digital IC generator system, only organs with ro¬
tating mechanical generators did not require tuning. The
new system is contained on a single pc board (JW x
14"), in contrast to the company’s former requirement
of 12 pc boards.

“10-Four, Good Buddy!” is a new board game by Park¬
er Brothers. The players act as truckers, driving their
tractor trailers down game board highways, using CB
radio consoles equipped with hi and lo frequency spin¬
ners that determine the number of spaces the trucks can
move. The game employs the special “trucker lan¬
guage;” players meet up with “Smokies” and a “Bear
in the Air,” and can get caught in a “BearTrap.”

Operation “Moonbounce”

Amateur radio operator Allen Katz, West Windsor,
New Jersey has become the first person to complete
two-way communication with all six major continents
via radio signals reflected off the moon. On a frequency
band similar to uhf television broadcast, and with a 28-
foot-diameter dish antenna in his backyard, Katz
achieved his goal. He was awarded a “Worked All Con¬
tinents” certificate by the National Amateur Radio Un¬
ion, headquartered with the ARRL.

Electronics for Autos

Tenna Corporation has entered into an agreement with
the Lincoln-Mercury Division of Ford Motor Company
to supply retractable Citizens Band antennas to be
offered as optional equipment on the 1977 Lincoln and
Mark V models. The rear-mount, electrically powered
antenna features a thin center-loaded coil, which en¬
ables the unit to be retracted completely when not in
use.

Rockwell International has agreed to supply General
Motors with the “Misar” spark timing system, which
will be standard on 1977 Oldsmobile Toronado cars. The
new system, the first use of a microcomputer in a pro¬
duction automobile, contains two LSI circuits with
more than 20,000 transistors and electronic elements.

AM Stereo Progresses

In response to a request by the FCC in the fall of 1975,
for a committee to study AM stereo, the National AM
Stereophonic Radio Committee was formed. At a recent
meeting, the committee evaluated proposals for AM
stereo systems, submitted by Communication Associ¬
ates, Motorola, RCA and Sansui. Transmitter and an¬
tenna perimeters for testing AM stereo were examined
and a list of test stations meeting criteria set by the com¬
mittee was developed. After these test stations have
been observed, the committee plans to submit its final
report to the FCC for Rule Making, The committee also
opposed a petition submitted by Kahn Communica¬
tions, Inc., which is also developing an AM stereo sys¬
tem, asking the FCC to deny their petition, and en¬
couraging Kahn to participate in the committee efforts
to ensure a standardized test procedure.

POPULAR ELECTRONICS

FLUKE PROVES AN INEXPENSIVE,

HANDHELD DMM
CAN BE BUILT WITHOUT LEAVING

EVERYTHING OUT.

Let’s face it.

Before now, if you bought an inex¬
pensive, handheld digital multimeter
you didn’t get much — they just left
most everything out.

We knew that was no answer.

So we built the 8030A 3 Vi-digit
DMM. It’s a small, portable, inexpensive,
handheld DMM, but it performs like our
benchtop units.

With one basic difference. The
8030 A was designed, built and tested to
a size and shape proven best for field
service and laboratory technicians. There’s
a built-in hood that can be slipped forward
to shade the readout in sunshine. It has
rms capability. The best overload pro¬
tection. Diode test. It weighs 2.2 pounds,
and will take a beating without failing.
Finally, we guarantee accuracy specifi¬

cations for one year.

And it only costs $235*.

True rms. Fluke

1 -year accuracy specs. Fluke

High voltage protection. Fluke

Diode test. Fluke

A full line of accessories offering rf voltage,
high current ac, high voltage dc, and
temperature measurement probes. Fluke

There’s only one place to go for all the per¬
formance you need in a handheld DMM.

There are measurement functions
in five selectable ranges for dc volts,
ac volts (true rms), dc current, ac cur¬
rent (true rms) , and resistance. DC volt¬
age measurement is from 100 pV to
1100V with basic accuracy of ±0. 1%,
ac measurement is from 100 pV to 750V
rms with basic accuracy of ±0.5%. DC
and ac current is from 100 nanoamps to
1.999 amps with basic dc accuracy of
±0.35% and basic ac accuracy of ±1%.
Resistance measurement is from 100 milli-
ohms to 2 megohms with a basic ac¬
curacy of ±0.4%.

We added true rms response for ac
measurements. Specified accuracy
is still attainable when the measured
waveform is distorted.

“ Fluke does the impossible again. ”

There is extensive overload pro¬
tection. It has been tested with tran¬
sients up to 6000V peak across the
input terminals.

Options include two battery opera¬
tions: a rechargeable NiCad for 8 hours
operation and throw-away alkaline cells.
Accessories include probes for measure¬

ment of rf voltages, high current ac,
high voltage dc and temperature.

80T-150 Temperature Probe

Sensitivity: _ 1 mV/°C or 1 mV/°F

Accuracy:

+ 15°C to +35°C ±2°C(3 . 6°F) — 25°C to
ambient: +125°C ±3°C(5.8°F)

-50°C to — 25°C and
+ 125°C to +150°C
0°C to 15°C,35°C Add 1°C(1.8°F) to
to50QC ambient: above _

You can also get temperature measuring
capabilities with the 8030A.

And because the 8030A gives you
so much in performance, let us remind
you once more of the price.

Only $235*.

For the first handheld DMM that’s
small in size, small in price, but huge
in performance.

For data out today, dial our toll-free
hotline, 800-426-0361.

John Fluke Mfg, Co. , Inc., P.O. Box
43210, Mountlake Terrace, WA 98043
Fluke (Nederland) B. V, P.O. Box 5053,
Tilburg, The Netherlands.

Phone:(013) 673-973 Telex: 52237

*U.S. price only.

A NEW ADVANCE. 8030A DMM. EtyH

DECEMBER 1976

CIRCLE NO. 31 ON REE INFORMATION CARD

BY KRIS CARROLE

Popular Electronics

DECEMBER 1976

Roundup
of TV
Electronic
Games

Video games are becoming almost
as popular as pocket calculators,
digital watches, and CB transceivers on
the consumer electronics scene. In fact,
suppliers don’t believe they can produce
enough TV games to keep retailers1
shelves filled during this Christmas sea¬
son of 1 976.

Connected to the antenna terminals of
any TV receiver, these new electronic
marvels pit one player against another
or against the machine in a variety of
games ranging from tennis to tic-tac-toe.
Some of the new video games illustrate
the on-screen graphics in color.

Magnavox got the video game market
rolling about four years ago with the in¬
troduction of its Odyssey® game. The
original game was basically paddles and
a white square that moved about on an
empty TV screen. The playing field, a
plastic laminate that physically attached
to the face of the picture tube, gave the

game boundaries, markers, and areas
from which to maneuver your “man” on
the screen.

It was not until fairly recently that
video games began to catch on as im¬
proved versions were introduced to the
market. Atari, makers of Pong®, is one
company that deserves a lot of credit for
popularizing the video game. Pong, a
game of table tennis, added some sig¬
nificant improvements: electronically
generated on-screen colored courts;
sound effects for every hit, miss, and ri¬
cochet of the ball; and automatic on¬
screen digital scoring. Add to this the
selling expertise of Sears, and you have
a notable contender for the projected
$750-million market by 1980.

There are currently some 35 compa¬
nies making video games. At this writ¬
ing, however, only 20 or so have had
their games type approved by the FCC
and are marketing games.

Tennis Anyone? Tennis (actually, ta¬
ble tennis) is available in all video
games in one form or another. The first
game of Odyssey gave player control
over the ball in both horizontal and verti¬
cal positions. Pong® and the newer
games give player control in only the
vertical position. Competition between
the new game makers has not grown out
of what moves a player can make but on
the games in which he can participate.
The new games still include tennis, but
now hockey and handball are typically
available at the flip of a switch.

The new Odyssey 400 now allows you
to play handball and hockey as well as
tennis and includes on-screen digital
scoring and sound effects. Atari’s new
Super Pong gives you a choice of the
original Pong tennis game, two-man
team tennis called Super Pong, Catch,
and Solitaire. Catch is unique in that it
allows you to control the position of a
“hole” in the boundary on your side of
the court. Solitaire is similar to a one-
man handball game, but the height of
the backboard wall is adjustable to make
the game easy or difficult. When you
play Solitaire, if you get the ball over the
wall, you make a point; miss on a return
bounce, however, and the machine
scores.

Games designed to pit your skill
against the machine are made by com¬
panies other than Atari and Magnavox.
In addition to tennis and hockey, First
Dimension has a clever Robot game
POPULAR ELECTRONICS

that has you trying to score by getting
the ball into a goal that is usually
blocked by a mechanized moving pad¬
dle. Coleco’s handball game has provi¬
sions for only one player to bounce the
ball off a wall at the far side of the
screen; you can miss, losing a point, but
the wall remains stationary, always re¬
turning the serve.

Unisonic gives you a choice of six
games, two of which are Skeet and Tar¬
gets. A white block, your target, random¬
ly crosses the screen. You shoot at this
target with an electronic gun supplied
with the game. Your score of hits is auto¬
matically displayed on the TV screen af¬
ter 15 rounds. Skeet and Targets are
slightly different in concept than other
games that merely use the TV screen as
a graphic display; in these two games,
the screen is an active part of the circuit¬
ry. A photocell inside the gun senses the
presence (or absence if you miss) of
light from the screen each time you pull
the trigger and updates the score ac¬
cordingly.

The Unisonic machine’s sound effects
are different, too. Rather than having the
sound come from a speaker built into the
game itself, the audio is modulated with
the video and sent to the TV receiver.
The sound is then reproduced by the TV
receiver’s speaker.

Universal Research has added a but¬
ton to give hockey a realistic twist. Or¬
dinarily, the puck can only be deflected
by players on the screen as with most

DECEMBER 1976

other games. A special “Puck Control”
switch on the Universal Research game
allows each player to catch and hold the
puck, passing off only when desired.
This is just one of the many switches
now appearing on the more complex
games.

In addition to the usual player position
controls, many manufacturers are incor¬
porating other controls to add to the skill
level requirements of their games. Pad¬
dle size, speed, and ball angle can all be
changed, either individually or collec¬
tively, depending on the switching ar¬
rangement provided in a particular video
game. Odyssey 300, for example, has
one switch with Amateur, Average, and
Professional skill positions. In the Ama¬
teur position, the paddle is large and the

speed and angle of the ball are mild. In
Average, the paddles become smaller
and the angle of deflection is increased,
but the speed remains the same. In
Professional, the paddles again become
large, but only to keep up with the large
deflection angles (40° versus 20°) and
high speed (0.65 versus 1.3 seconds
across the screen) of the ball while it is
in play.

APF uses three separate switches to
allow the player to tailor the game to the
way he wishes it to be played. First Di¬
mension allows just the speed of the ball
to be changed, but each player is provid¬
ed with a separate speed control, which
is a bit more practical because each
player can be separately handicapped.
Other switches on some games permit

NatkinaJ Sern i no ndu HOf'S Adversary

two or four players to participate in the
game and provide automatic and manu¬
al serve selection.

The game selector switch sets up the
playing field for the particular game you
wish to play. While the graphics are gen¬
erally set up in the same manner by
each manufacturer, there are differ¬
ences here, too. National Semiconduc¬
tor’s Adversary game, for example, al¬
lows you to play tennis on a green court,
hockey on blue “ice,” and handball on a
brown “clay” court when used with a col¬
or TV receiver.

1C Technology Base. What has
been primarily responsible for bringing

video games down to practical size and
price is the LSI integrated circuit tech¬
nology support the industry has re¬
ceived. For many game manufacturers,
the General Instruments dedicated n-
channel MOS chip is used. (There are
separate chips available for U.S. and
European TV standards.) The 28-pin 1C
contains all the logic required for tennis,
hockey, handball, and practice. With
slightly more outboard logic, this chip
also provides target and skeet game
modes that are played with a remote
electronic gun. Score update and dis¬
play for all games are also on-chip gen¬
erated for these IC’s.

Input programming pins on the Gener-

HOME VIDEO GAMES

Brand

Model

Price

Games*

Players

Color

Remarks

APF

401

1,2, 3, 4

?,1

Atari

Pong

yes

Super

4th game, Super Pong, is

Pong

1,7,8

2,1

yes

ten. dbls. {4 players)

Coleco

Telstar

1,2,4

~2/i

Tel star

same as above except

Classic

1.2,4

2,1

cabinet and ac operation

Dyn

Paddle

Four

1,2, 3, 4

j~27i

Ralley

Four

80.

1,2, 3, 4

2,1

same as above except
cabinet different

Enterprex

Apollo

1,2,3, 4

2,1

Entex

Tele

1.3,4

2,1

H-V control on tennis.

Pong

4th game, table tennis
has V-control only

Executive

r tv”"

1.2

manual scoring

Games

Tennis

Hockey/

Soccer

360° player movement,
puck control

First

1 .2,3,4

2,1

Dimension

76C

1,2,3, 4

2,1

yes

same as 76, with color

3000

on-screen moving bar

100

1.2,9

4,2,1

for score

Heath

GD-1380

1 ,2,3,4

2,1

Video output. Can be used
only with Heath kit TV receivers

Kings Point

TG-600

1,2, 3, 4

2,1

Lloyds

100

1-6

2,1

Monte

Verde

100

1-6

2,1

same as above except
cabinet different

Magnavox

200

1.2,3

H-V player movement. On¬
screen moving bar score

300

1,2,3

400

100

1,2,3

yes

H-V player movement.

English control.

Micro¬

electronics

Ricco-

chet

120

1,2, 3, 4

2,1

yes

var. color, English

National

Adver¬

100

1,2,3

2,1

yes

time-out button

Semiconductor

sary

Phoenix

Video

Sports

1,2, 3, 4

2,1

Quadtronics

Q-376

1,2, 3, 4

2,1

yes

second model, $80, same
but with remote controls

Radio Shack

60-3050

1,2, 3, 4

2,1

Tele-

4400

1, 2,3,4

2,1

Match

7700

1,2, 3, 4

2,1

same as above except
cabinet

Unisonic

2000

120

1-6

2,1

Universal

Video

120

1,2,9

2,1

yes

Research

Action

III

* NCC •
Vss (Ground) C 2
Sound Output C
VccC
Ball Angles C
Ball Output C
Ball Speed L
Manual Serve C 6
Right Player Output C 9
Left Player Output C 10
Right Bat Input C 11
Left Bat Input C 12
Bat Size C 13
*NCC 14

DNC*

3 Hit Input
3 Shot Input
3 Reset Input
3 Score and Field Output
3 Pelota/Practice
3 Squash
3 Hockey/Soccer
3 Tennis
3 Rifle Game 2
3 Rifle Game 1
3 Clock Input
3 Sync Output
3 NC*

Pin configuration of General
Instrument’s AY-3-8500 game chip .

al Instruments chip permit direct non-
buffered switch connections for game
selection, ball speed, paddle size, and
four different ball-return angles. Other
inputs provide for automatic and manual
ball serving after each point is scored
and separate resetting.

Separate video outputs from the Gl
chip allow combining for a monochrome
or use with a color generator for a color
picture display. An audio output pin on
the 1C can be used to deliver a signal
that can be modulated with the video
signal or buffered through a one-transis¬
tor circuit to drive a loudspeaker.

The flexibility of the Gl chip makes it
quite attractive to video games manu¬
facturers. Game complexity, which de¬
termines the manufacturing cost, is basi¬
cally a matter of whether or not a given
pin on the 1C is used. All that must be
added to the primary circuit are a 2-MHz
clock generator, r-f modulator for TV
Channel 3 or Channel 4, paddle control
potentiometers, loudspeaker, and power
supply. The power supply is usually a
set of six C cells, which may or may not
be supplied with the game.

The game Adversary is quite naturally
designed around National Semiconduc¬
tor’s MM57100 videogame and LM1889
video modulator chips. In addition to
providing three selectable skill levels,
Adversary allows an opponent to play
against another opponent, against him¬
self, or against the machine. A special
"time-out” feature stops the play instant¬
ly, with no effect on the game. (The usu¬
al reset function returns all scores to 0
and initiates a new game.)

Texas Instruments has also gotten
into the video-games market, but not
with a finished product that bears its
name. Tl is offering six separate chips
that can be combined in different arrays
to create a range of video games from
simple to complex. The Tl chips current¬
ly being offered include: game logic with
automatic random English, horizontal
and vertical sync generator, game logic

*1— tennis, 2-hockey, 3-handball, 4-practice, 5-targets, 6-skeet, 7-solitaire, 8-catch, 9-robot.

POPULAR ELECTRONICS

Mallory CA3 Intrusion Alarm
and ABA1 Car Alarm.

With Mallory
Security
Products on
the job,
intruders
get the
message
loud and
clear.

Anyplace, anytime. For the few dollars they
cost, here are mighty effective ways to signal
forced entry of a building, home, apartment,
office, automobile.

Put the Mallory CA3 Intrusion Alarm in
your living room, for instance. It’ll easily
pass for a radio or stereo tuner
while transmitting a 20-foot
ultrasonic wavelength field.

One that will detect the
slightest intruder movement
and activate an alarm.

This compact area-and-

.rrr-

-«V\

perimeter
device
comes with
solid-state
circuitry and big
reliability. And a wide variety of indoor and
outdoor warning accessories to choose from
—bells, horns, sirens, rotating red lights,
tape switches, many more.

For automobile security, install the Mallory
ABA1 Car Alarm with entry sensing and instant
siren alert for doors, hood and trunk. It comes
as an easy-to-in stall kit, complete with
switches, wire, keys, warning decals.

From any angle, Mallory
Security Products mean
protection. See your
Mallory distributor. Or
send for our Security
Products Bulletin
No. 9-654.

MALLORY DISTRIBUTOR PRODUCTS COMPANY

a division of P. FL MALLORY & CO. INC.

Box 1284. Indianapolis. Indiana 40200: Telephone: 317-850-3731

Capacitors • Controls • Security Products • Recording Tapes • Resistors • Semiconductors • SONALERT® • Switches • Fastening Devices

SONALERT® is a registered trademark of P. R. Mallory & Co. Inc.

DECEMBER 1976

CIRCLE NO. 44 ON FREE INFORMATION CARD

with manual English, wall and ball gen¬
erator, character generator, and digital
scorekeeping IC’s. Tl plans to supple¬
ment this lineup with other chips in the
near future.

In spite of the wide acceptance of
dedicated video-game IC’s, Fairchild’s
new game (not available at this time)
may set the trend for all video games for
the future. Built around the F8 micro¬
processor and four random-access
memory (RAM) chips, the Fairchild
game is unique because it can be exter¬
nally programmed with a special “Video¬
cart” and a keyboard on the player con¬
sole. Similar to a cassette tape, the Vi¬
deocart reprograms the system for a
new selection of games other than the
system’s resident tennis and hockey
games. You simply consult the jacket of
the Videocart for the particular game
you would like to play and use the key¬
board to punch in the game number.
Skill levels and even time limits can be
added at the console.

Fairchild intends to market the Video¬
carts for about $20 each. The first car¬
tridge contains programming for a tic-
tac-toe game, shooting gallery, and a
doodle game that allows you to draw in
color on your TV receiver’s screen. Fair-
child expects a total of 17 games to be
available by Christmas.

As a point of interest, the use of a
computer-based video-game system,
which is the idea behind the Fairchild
game, opens possibilities for using your
TV receiver as a serious tool for learning
and storing information. One Videocart
might contain a question-and-answer
quiz for students, while another might be
programmed with a host of cooking re¬
cipes. The possibilities of such a system
are limited only by the imagination of the
user. Greg Reyes, Vice President and
General Manager of Fairchild’s Con¬
sumer Group, sees it as “opening up a
flexible capability for future TV-based
applications.”

Adversary game.

Hooking It Up. Since all video games
contain their own modulator for the
video (and sometimes the audio) signal,
they simply connect to your TV receiver
via its vhf antenna input terminals. Each
game manufacturer supplies a small r-f
switching box that accepts an input from
the game console and another from an
external standard TV antenna. Once the
system is hooked up, you can select
either the tv or the game position of the
switch as desired. A second switch,
which is usually buried inside the game
console, allows selection of the modula¬
tor frequency for either Channel 3 or
Channel 4. •

Ironically, the simplest section of the
video game’s circuitry has been the
cause of a great deal of trouble for the
game manufacturers. Since video
games are r-f generating devices, they
must meet the requirements of Part 15
of the FCC’s Rules and Regulations.
There must be a minimum of 60 dB of
isolation between the video game and

TV antenna to keep the game signal
from exceeding the 15-pV/m limit of ra¬
diation from the antenna set by the FCC.
Unless the tv/game selector switch can
provide the necessary 60-dB minimum
isolation, the game will not receive FCC
type acceptance.

There is an alternative to the r-f prob¬
lem that eliminates the need for a modu¬
lator — direct video access to the TV re¬
ceiver with which the game is to be
used. Unfortunately, there are not many
TV receivers around that provide this ac¬
cess. Magnavox, however, plans to offer
a 1977 TV receiver with a built-in video
game. The game will feed directly into
the video amplifier section of the receiv¬
er, bypassing the r-f and i-f sections of
the receiver. Once the trend gets start¬
ed, TV receivers of the future are likely
to have video input jacks as standard
equipment. Such jacks will not only
accommodate video games, but they
will also accommodate video tape re¬
corders and video discs. O

Hockey game on a
TV screen. Courtesy
First Dimension.

Fairchild’s new game
(not available at time
of writing) is built
around the F8 MPU
and four RAM’s.

POPULAR ELECTRONICS

BY ROBERT COLMAN
AND TOSHiAKJ OKAWA

BUILD A

Decodes SQ and QS
or provides surround
sound or concert hall
enhancement to stereo.

Universal 4-Channel
Matrix Decoder

FOUR-CHANNEL sound can pro¬
duce a new, welcome audio dimen¬
sion, approaching a live performance
ambience. Although it has not yet cap¬
tured the consumer’s fancy in the man¬
ner that stereo did (for reasons such as
higher cost, multiple quadraphonic sys¬
tems, and poor separation with earlier
systems), it is slowly but surely moving
into the marketplace.

With more and more matrix 4-channel
FM broadcasts available around the
country and lots of matrix-type records
that use standard stereo cartridges,
quadraphonic sound promises to grow
in importance over the years.

The universal decoder presented here
features the advanced QS vario-matrix

approach used by Sansui, and will oper¬
ate with SQ (producing the equivalent of
“half logic” SQ) and other matrix-encod¬
ed media. Additionally it can synthesize
four channels from existing two-channel
sources, yielding a choice of simulated
quadraphonic sound or “Surround
Sound,” each with 20-dB separation. A
complete kit is available for $75 plus $1 2
for an attractive case. As illustrated in
Fig. 1, the circuit employs only four
unique IC’s and a handful of transistors.

Circuit Operation. Essentially, the
QS vario-matrix analyzes where the re¬
produced sources are coming from, and
adjusts the matrix parameters to cancel
out the inter-channel leakages that are

normally present in simple matrix decod¬
ing. This approach is in contrast with the
gain-riding logic that attempts to alter
the gain of the four channels to reduce
the undesired inter-channel crosstalk.

As shown in Fig. 1, the two-channel
audio enters the system via the LT (left)
and RT (right) input jacks. After a stage
of gain (Q01-Q02), the signal splits into
two paths.

One pair of signafs (marked A and B
in Fig. 1 ) is used to drive the two phase
discriminator IC’s (HA 1327) that use the
phase and level signals between the
Uotal and Rfotal encoded signals to de¬
tect the location of the predominant sig¬
nal. The outputs of these two IC’s then
become four control signals — right, left,

What is QS?

QS is the trademark of Sansui Electric
Company of Japan for its 4-channel matrix
encoding and decoding system. This is a
symmetrical matrix that is totally compata-
ble with any simple matrix decoder (RM,
Dynaco, etc.), or vario-matrix decoding.
What is SQ?

SQ is the trademark of CBS Inc. for its 4-
channel matrix encoding and decoding
system. This is a nonsymmetrical phase
matrix that uses phase-shift networks to
provide the decode function and logic ac¬
tion to produce the interchannel separa¬
tion.

What is a Synthesizer?

This is a circuit that accepts conventional

FOUR-CHANNEL DEFINITIONS

2-channel (stereo) sources from records,
tapes, or stereo broadcasts and creates a
4-channel simulation.

What is the Surround Mode?

This mode uses stereo-to-4-channel simu¬
lation so that the sound emanates from all
four speakers to “surround” the listener as
if he were positioned on the conductor’s
podium, or almost in the middle of the or¬
chestra or group performing.

What is the Had Mode?

In this mode, the listener is acoustically po¬
sitioned “up front and center” with the
stereo stage presented across the front
while the ambience is at the rear with 20
dB separation between front and back.

Does QS or SQ require a special car -
tridge /stylus?

Only carrier disc demodulation systems
(CD-4) require a special cartridge/styius.
The QS or SQ system can use any high-
quality stereo cartridge/stylus combina¬
tion.

What is the difference between vario-
matrix and phase matrix?

Vario-matrix achieves high separation be¬
tween channels by altering the matrix pa¬
rameter dynamically during decoding.
Phase matrix achieves its separation by
varying the gain of the channels according
to the loudness of the desired signal, and
uses logic to decrease the effect of un¬
wanted crosstalk between channels.

DECEMBER 1976

nsr? np

in rr;

— Wv-

HI - 1

Fig. 1 . Schema tic of decoder is shown above and on opposite page.
Parts List includes power supply shown in Fig. 3.

PARTS LIST

Cl, C34. C35, C36, C37, C42, C46, C47,
C81, C82 — 10~pT\ 25-volt radial electrolyt¬
ic capacitor

C2, C2 1 , C45, C48, C75, C83, C91— 3.3-pP,
16- volt radial electrolytic capacitor
C3, C18, C44 — -O.01-|iF, 5% capacitor

C4, C8, C20, C22, C41, C53, C86, C96,
Cl 09, Clll — l-pf, 16-volt radial elec¬
trolytic capacitor

C5, C25, C38, C54, C71, C100, C101— 470-
pF, 5%, styrene capacitor

C6, C 1 9, C39, C5 1 , C66, C 1 1 3—0.0 1 -\xF ca¬
pacitor

C7, Cl 6 — not used

POPULAR ELECTRONICS

C9, C17 — 1-p.F, 16-volts, axial electrolytic
capacitor

CIO, C26, Cl 08 — 0.0068-(ulF capacitor
Cll, C12 — 100-p.F, 10-volt radial electrolytic
capacitor

C13, C24, C28, C33 — 47-pP, 25-volt radial
electrolytic capacitor

C14, C15, C49, C50, C88, C98— 0.033-pT
capacitor

C23, C27— 100-pF, 5% styrene capacitor
C29, C30, C3 1 , C32 — 3300-pF capacitor
C40, Cl 10, Cl 12— 0.01 2-pJF capacitor
C43 — 0.0047-p.F, 5% capacitor
C52, C107 — 0.015-jjlF capacitor
C55, C59 — 330-pF, 5 % styrene capacitor
C56, C57, C58, C84, C94, C95— 0.001-pP.

5% capacitor

C60, C72 — 0.0039-pP, 5% capacitor

C61 , C62, C73, C74, C77, C78, C102, C103,
Cl 16 — 4.7-pP, 25-volt radial electrolytic
capacitor

C63, C85 — 0.068-pT capacitor
C64, C65, C87, C97, C106— 0.056-jxF capa¬
citor

C67, C68, C89, C90— 0.0022-p.F capacitor
C69, C70 — 0.033-fiF capacitor
C76, C79, C80, CIQ4— 33-p.F, 25-volt radial
electrolytic capacitor
C92, C93 — 0.068-pP, 5% capacitor
C99, C 1 05 — 0.0 1 8-jjlF capacitor
Cl 14 — 0.01-p.F, 50-volt, ceramic capacitor
Cl 15 — 1000-p.F, 35-volt electrolytic capaci¬
tor

Cl 1 7 — 220-pF, ceramic capacitor
Dl through D6 — 1N914
D7 through DIO— 1N4001

FI — Vi-ampere slow-blow fuse and holder
IC l— HA 1328 (Sansui)

IC2, 1C4 — HA1327 (Sansui)

1C3 — HD3 1 03 (Sansui)

1C5 — 723 voltage regulator
J 1 through J6 — phono jack
LED 1— red LED
Ql, Q2 — MPSA55
Q3 through Q10 — 2N3391A
Ql I — 1 -ampere npn power transistor
The following resistors are 14-watt, 5%, un¬
less otherwise noted:

R1 — 5600 ohms
R2, R1 1 — 47,000 ohms
R3, R13, R60, R63, R73, R76, R167,
R169— 1000 ohms

R4, R14, R20, R21 , R62, R65, R75, R78,
R129, R135, R149, RI52— 100,000 ohms
R5, R6, R8, R10, R12, R15, R17, R19, R27,
R166, R 168— 2200 ohms
R7, R16, R176— 3300 ohms
R9, R18, R31, R38, R39, R40, R41, R55,
R57, R68, R70, R157— 22.000 ohms
R22, R24, R30, R 165— 1500 ohms
R23, R87, R88, R104, R 106— 6800 ohms
R25, R34, R35, R105, R107— 68,000 ohms
R26— 18,000 ohms

R28, R66, R85, R93, R96, R97, R101, R103,
R109, R1 1 1, R1 15, R1 16— 120.000 ohms
R29, R86, R 94— 390,000 ohms
R32, R89, R134, R137— 33,000 ohms
R33,R175— 8200 ohms
R36, R37— 27, 000 ohms
R42, R43, R44, R45^T7 ohms
R46, R47, R48, R49, R131, R132— 15,000
ohms

R50, R51 , R52, R159, R161— 1200 ohms
R53 — 150, OCX) ohms

R54, R56, R58, R59, R67, R69, R71, R72,
R80, R8 1 , R83— 220,000 ohms
R61 , R64, R74, R77, R150 — 4700 ohms
R79— 3900 ohms

R82, R91 , R100, R102, R108, R110, R113,
R127, R141,R 144— 330,000 ohms
R84, R92, R 122, R 125— 270,000 ohms
R90, R95, R1 12, R1 14—680,000 ohms
R98, R99, R1 17, R1 18, R1 19, R120, R164,
R170, R1 7 1—56,000 ohms
R121 , R 1 26 — 1 .5 megohms
R123, R124, R 1 40, R 145—560,000 ohms
R128, R130, R148, R153— 1 megohm
R133, R136 — 560 ohms
R138, R147 — 2.2 megohms
R139, R142, R143, R 146 — 470,000 ohms
R 1 5 1 , R 1 54, R 1 77 — 2700 ohms
R155,R 156— 12,000 ohms
R158 — 10,000 ohms
R 1 60, R 1 63 — 680 ohms
R 162— 120 ohms
R 172— 2000 ohms
R173 — 2.4-ohm, Vi- watt
R174 — 1500-ohm trimmer potentiometer
SI — 12-position, 4-pole rotary switch
S2 — spst switch, 3-ampere rating
TI — 30- volt secondary
Misc. — Suitable enclosure, line cord, shielded
cable, hookup wire, hardware, etc.

Note— The following are available from Pho-
tolume Corp., 1 18 E. 28th St., New York,
NY 10016: kit of 1C1 through 1C4 with
etched and drilled pc board, #QSP-3 at
$25; complete kit of aM parts except case,
#QSK-3 at $75, plus $2 for shipping (Cana¬
dian and foreign, add shipping and insur¬
ance for 4 lb); drilled and screened case at
$12. New York state and city residents, in¬
clude appropriate sales tax.

DECEMBER 1976

Fig. 2. Actual-size etching and drilling guide above , components placement on opposite page .

back, and front — that are passed to con¬
trol 1C (HD3103). This 1C, containing five
FET's, generates the dc voltages that
are used to vary the parameters of the
phase-matrix IC-HA1328.

The second signal path feeds the
phase-matrix transistors Q03 and Q04 ,
whose outputs go to the HA1328. In the
matrix 1C, the incoming audio signals
are combined with the control signals
from the HD3103 to produce four audio
outputs — L front, Rfrorrt, L, back , an^
40

Rback with a better than 20-dB inter¬
channel separation. These signals are
then passed through cross-coupled
emitter followers (Q07 through Q10) to
form the actual output signals.

The technique involving the use of a
symmetrical variable encoding/decod¬
ing matrix (vario-matrix), and controlling
it with signals derived from the phase re¬
lationship of the two encoded channels,
enhances the separation between any
pair of the four decoded channels. The

same vario-matrix can be used to en¬
hance the reproduction of conventional
2-channel stereo signals into an excel¬
lent simulation of 4 channels because, in
conventional stereo recording, the ma¬
jority of the left and right signals are in
phase with each other. Even when some
of these signals are out of phase, the re¬
verse-phase components are minimal
compared to those components that are
in phase. If the reverse-phase informa¬
tion could be added to the in-phase,
POPULAR ELECTRONICS

; 3

f §5

“It

Q- O

082:

T?-
I ° 3-

8 2 ?
si

ill

- s N W
0 *<
Cl W
^ — CD

a. «P 2

CD 3

"S- o'

3- 3
0 0.
0 (/>

=r. 0
o o

0 S

O CL

3 3'
0 tp

-1

<’

§*
* £

- 5
0 o
0 c

? s

o *o

3 O
_ 0

? ft
§ 2
o 0

^ ft
g 3

3 o
* 0
~ CO
O’ 3
0 0
— 0
0

m 0
0 =i

3 0
0

^ O

s.g

5 8
< ^
0 ^
^ O

9- 0
ft?
5‘ 0
o 0

005

00^

»® 3

0 3 §
00

= 1 1

JO “
® 3 ^
S 0

o
0 *5

3 o

0_ CL

? 3

: 0 S

wj £
C T3 0
3 0 r7

g 0 «

§ CO s
Q. ft Z

* 3 ®
3 0 ~

§.3 0
0BJ0

E? ? O'
0 O T*

0
0
0
O
0

<9* b

o
3
o
0

?
I
0

ft
0

0
— *

0
3"

0
0

§ 3

n* o

o a.
3 P

o -o

-I 0
0 O
■O O

3 CL
o 0
Q. -1

a 8

5' 3
3 »

S o
3 o*

0 ®
o c
c 0

0 CL
T3 =;*

<p 0
0. O

0 O

0 0

-t

3 §

5 Er
0 0

_. o

CL 3

ft g-

n &

O O

53-

0 T3

8 |

T3 p

3 O

0' ft V !=;

d 0

« §

0* i.

^ 3
o to

“ft =r

0 o

0 3
0 3

3 £
0 _

=: O
0 C

U-TR RTGr.
1 TOSW2 L

LINE

CORO

T 1

i<*

c / V

<t ? x.

1 m r.tbi R

R* *
96 *

•457-*

*R%*

•on*

•R168.
4 *0111*

cVk

•-CT1- « . +

v »K8e- ®p * c7£

^ 4^ Rfe7°* *U91-*

? 1 iz l *-«*-

N*M-

11
♦.R

tf.

HA EOT

C 115

_ TR MTGr.

CI“ Ui

p7 |D9 |D1( jp

C+l

Qtl

“4

M 723

_rx__

T ^ "*ClA ^ t C/,

C w • *R92"# C 104

4 •CIU^ \qi •„ h * # • r72 9 **4-

«<• ..... •**

1ll«L ^ RUHR . ^a. ,

KlWl iui£7»ioe;o^c8+-« J

■R104* 1 * * trt , ^

•-CS5

c ?+, ‘
• +R1R>

sK-‘ 1

5- *•&* *-&-

IT* *&• -i&-

<7 » ,

4, y

R14-* ^
^R15

css

. \ T t
\ t T f

V R«, * J

*15 * 40* 4 L - 1

*&■ 1% \ k ¥*$17 ^ +'119 J \+ nn \+ 1

2gtt.u* /\!TfT \\c4C

',cm ,:ih A k s i JL Ll.a %2j 1111 . ?a> "*45

ft&2

•ci09> g s . » * i & s

f t ■prj4

_ c _ S ; S ^ ^

■fr

f*1/* f Rffi FU27

^.cr -c-

*-R , -RBO*

/ i 1 1 t 7

+ T1 Ln I i ^ *\2

f” 1 ! *•*• Bfij^

‘96-

^R Rf

^ Jb

-C49- f
R&9

. ^ b iSael Vc0

R57-Cfi" # c # +-

K \ ^ T r -C20

*,R Kd ^ ^

*• ^ ; % w

J! •*• A £ ^

♦rC41»

3103P 74" R^9 ^5.

riT ,1W ^ lV ’5 f1^

n"'Mc.Lfe*

k cp i

?i 1 < ? T

•p, R1

c j » . • tiL* ^

M , * (f , R 42

w l0/1/ f ; °-

4 „rA rt. *+.&n raE7 « ^

f t /Wt

4 & s£ £ 4. * *k&. 4 °‘

Nc i»a 193^40 c O

>" - 1 X . **■

0—

o—

2 l?T INPUT
35

1 Lt imput

- 34

- 32

- 27
-26
-21
-22

- 23
-24

ROTARY

SWITCH

— G SWITCH

— 6 Lf
”7 Rf

“ s Lb OUTPUT

“9 I?& OUTPUT

— Gr SIGNAL

R173

Fig. 3. Schematic of the power supply.
Components are given in Parts List for Fig. L

coded with the CBS SQ system (a
phase-matrix technique). The four out¬
puts (LF', RF\ LB' and RB') are equiva¬
lent to the outputs from a basic SQ de¬
coder with partial logic. This provides a
corner separation of between 3 dB and
infinity. Application of the vario-matrix to
phase-matrix decoding provides a great¬
er separation between CF (center front
and CB (center back) than the basic SQ
decoder.

Construction. Although any type of
construction can be used, the complex¬
ity of the circuit can be greatly reduced
by using the single-sided foil pattern
shown in Fig. 2, which also shows the
component installation. Because of the
board density, most of the resistors are
mounted vertically. Sockets should be
used for the IC’s. A low-power soldering
iron (25 watts) with small-gauge rosin-
core solder is used to mount the compo¬
nents. Check the polarities of semicon¬
ductors and electrolytic capacitors. After
component installation, look the board
over for accidental shorts between the
closely spaced copper traces. Note that
a well-regulated power supply (Fig. 3)
using an 1C regulator and series pass
transistor (with slip-on heat sink) has
been incorporated on the board and the
+Vqc is connected to the main portion
of the board via a small jumper (J1). Do
not connect this jumper at this time.

To select the four functions — SQ, QS,
Surround, and Hall — a four-position, 12-
pole rotary switch is wired as shown in
Fig. 4. Note that seven components are
mounted on the switch, while all the oth¬
er connections are made to numbered
pads on the board. The switch should be
pre-wired with sufficient cable length to
reach the board after the switch has
been mounted on the front panel. Multi¬
conductor cable makes for the best ap¬
pearance. Power-on LED1 is also
mounted on the front panel with a suffi¬
cient length of insulated pair to connect
it to the pc board.

The finished pc board without the IC’s
installed (except for the power supply
regulator), should be tested before in¬
stalling it in a cabinet. (The prototype
used a Ten-Tec MW-8, having dimen¬
sions of 4 3/16" high, 6 5/16" deep by 7
13/16" wide.) Drill suitable holes in the
front panel for the function selector
switch, power on-off switch, and LED1.

The six phono connectors — two for in¬
puts and four for outputs, can be mount¬
ed on the rear apron and suitably identi¬
fied. The power line can exit via a grom-
metted hole on the rear apron.

The system requires only one adjust¬
ment— the power supply voltage level.
Using a dc voltmeter connected be¬
tween the positive output of the supply

I - SQ 2 = QS 3= SURROUND 4 = CONCERT HALL

Fig. 4. Some components are mounted on function switch.

DECEMBER 1976

(jumper J1) and ground, turn on the
power and note that LED1 glows, then
adjust trimmer potentiometer R1 74 for a
meter indication of 25 volts. Once this
adjustment has been made, turn off the
power and connect jumper J1 into place.

Install the IC’s, identifying each pin 1
by its index cutout and dimple. Take a
last look at the board checking for cor¬
rect component installation, then turn on
the power. The front-panel LED should
come on. Using the dc voltmeter, check
the Vqq line at each of the points where
the voltage is applied, according to the
schematic. If the dc voltage at any point
is off by more than 15%, there is an in¬
correct condition that must be cleared
up before going further. If the power
supply is functioning properly and the
voltages at the IC’s are incorrect, re¬
check the wiring and component instal¬
lation. Install in the cabinet.

If all dc checks are good, connect the
decoder into an operating system such
as that shown in Fig. 5.

To make a final system check, the use
of a QS encoded test record is suggest¬
ed. One of these, the Ovation Records
OVQD 4000, features musical and test-
tone sequences to demonstrate that the
proper channel locations and separa¬
tions are being achieved.

To test the synthesizer mode, a
stereo record such as Pink Floyd’s
“Dark Side of the Moon” (SMAS-1163),
using the cut “Money,” will show the
quality of synthesized four-channel mu¬
sic that can be obtained from a stereo
disc.

To test the concert hall mode, any

good classical recording with reason¬
ably good ambience will demonstrate
the desired effect.

For SQ testing, either an SQ test rec¬
ord, or a musical selection such as the
Bill Chase recording “Chase” (EQ-
30472), using the cut “Open Up Wide,”
can be used. O

Get More from Ybur

Car with a
System.

The best-selling CDI system of its kind in
the world — now at discount prices!

Would you like more power? Better
And could you stand to eliminate 3 out
of those expensive tune-ups? Well, that’s
what the MARK 10 capacitive discharge
electronic ignition system is all about. Very
simply, it boosts the spark to your engine —
promoting better combustion, and minimizing
combustion contaminants. Spark plug
life is extended, all-weather starts
are insured, and you can feel an increase
in acceleration and overall engine
performance — no matter what kind of
car you drive. Learn more about a
MARK 10 CDI system for your car (and
take advantage of year-end discount prices),
when you write today for a catalog and price list

.State .

DELTA PRODUCTS, INC.

RO. Box 1147, Dept. PE
Grand Junction, CO 81501
(303) 242-9000

I want to know more about Mark Ten CDI's.
Send me complete no-nonsense information on
how they can improve the performance of my car.

Name _ _ _ _

Address _

POPULAR ELECTRONICS

CIRCLE NO. 21 ON ffiEE INFORMATION CARO

Three"pouier mike
jift ideas
ram Telex,

“Power mikes?” you say, "but two of
them look like headsets." And you're
right! And if you’re a seasoned CBer

m ready to move up, take a second look at the aviation-type Telex CB-88

I ffl A A A power-mike headset. Your CB listening is private; lets others around you
visit, relax or sleep without a blaring speaker. You hear better and
P m transmit better. Weighs less than 3 oz. Uniquely, you can wear it

BpimAmMra TaIAII without the headband by attaching it to your eyeglasses (adapter

I ■HIHjK included). Check out the CB-1200, especially right for high-noise

environments, and the aviation-inspired Double-Header power
mike. Then move up to Telex, the quality standard of the aviation communications industry now producing
the most powerful CB gift ideas around. And if you want to drop a loud-and-clear hint, just tear out this ad
and leave it where your gift-giver will find it... or take it to your Telex CB dealer for a gift-idea demonstration.

Can be worn
without headband .
Easy-to-use
eyeglass adapter.

Fully adjustable
head band.

Fully cushioned
for comfort.

Boom pivots for
leftlnght ear.

Fully cushioned
to block out .
highway and '
vehicle noise .

Both headsets
include in-line
push-to-tilk switch.

Noise-cancelling
variable-gain
power mike.

v. Soft earpiece
adjusts to fit.

High quality mike
with fixed-level
FET amplifier.

Boom adjusts
for precise
mike position.

Use as conventional
power mike
or as superior
noise-cancelling , %
power mike thanks
to Double-Header feature.

Adjustable mike boom,
310 0 swivel,
close to lips.

Built-in variable
gain power amplifier.

Style used by
pilots around the
world, fits every hand.

Front mount ends
mike fumbling.

Mike comes off bracket
in talk position.

Rear mount also included.

Long-life
coil cord.

The Pilot People

COMMUNICATIONS, INC.

9600 Aldrich Ave. So.. Minnepolis. MN 55420 U.S.A.
Europe: 22 rue de la Legion d’Honneur 93200 St. Denis. France
Canada: Telak Electronics, Ltd., Scarborough, Ontario.

Measure the sun's energy with

A SOLAR RADIOMETER

WITH INTEREST in alternate
sources of energy at an all-time
high, a definite need exists for simple,
reliable instruments to aid the experi¬
menter. This project — a solar radiome¬
ter — is one such device. It will enable
you to plan and set up solar energy con¬
verters with maximum efficiency.

Solar radiometers are by no means
new. Many of us have seen Crookes ra¬
diometers, which are partially evacuated
glass bulbs containing rotating vanes sil¬
vered on one side and darkened on the
other. When exposed to bright light,
temperature imbalance causes the
vanes to spin. The brighter the light
source, the faster the vanes will move.
But such devices are really “conversa¬
tion pieces.” Commercial instruments
which measure solar radiation accurate¬
ly are very expensive. But this project,
composed of a silicon solar cell, a mil-
liammeter, and a shunt resistor, will
measure the amount of sunlight falling
on a given area. It will do so with reason¬
able accuracy (about 5% if the specified
components are used).

Circuit Theory. The solar cell used
as a light detector in the radiometer is
really a large pn junction (like a diode)
with one side exposed to light. Leads
are attached to each side of the junction.
In the presence of light of the proper
DECEMBER 1976

BY WARREN JOCHEM

wavelength, a voltage will be generated
across the two leads. When a silicon cell
is placed in bright sunlight, a high-
impedance voltmeter will measure about
0.6 volt across it.

If a resistance (in this case a meter
and shunt resistor) is connected to the
output leads, a current will flow. Reduc¬
ing this resistance to a very small value
(0.3 ohm in this circuit) means that the
solar cell is effectively working into a
short circuit. It can be shown that the
short-circuit current is directly propor¬
tional to the intensity of the light falling
on the cell. Also, the short-circuit current
is largely independent of temperature.
This is important to the accuracy of the
meter if it is exposed to a wide range of
ambient temperatures. Actually, the cur¬
rent does increase slightly with heating.
If the meter is left in the bright sun for a
while, its readings might be a bit on the
high side.

The radiometer is calibrated in “Lang¬
leys per minute,” a unit which might be
unfamiliar to some readers. This unit
was chosen because it is the standard
used in most solar research today. Ac¬
cordingly, you will find comparisons of
your experimental data with existing re¬
cords a very simple process as no con¬
versions are necessary. By definition,
one Langley per minute is equivalent to
one gram calorie of energy falling on a

surface area of one square centimeter
for one minute. In other words, one
Langley per minute represents enough
energy falling on one square centimeter
in one minute to raise the temperature of
one gram of water one degree Celsius.
This statement is expressed mathemati¬
cally by the equation:

1 Langley _ 1 gram calorie
minute ” cm2 minute
For those who do not yet want to go
metric, and who are more familiar with
BTU’s, the equation is:

1 Langiey 221 BTU
minute ft2 hour

In words, this means that one Langley
per minute represents the energy falling
on one square foot in one hour required
to raise the temperature of 221 pounds
of water one degree Fahrenheit.

The peak insolation (incident solar ra¬
diation) measured at sea level is about
1 .6 Langleys per minute. With this max¬
imum in mind, the circuit has been de¬
signed so that the meter reads 1 .7 Lang¬
leys/minute full scale in 0.1 -Langley/
minute increments. Over the course of
one year at the author’s New Jersey lo¬
cation, the peak insolation varies from
about 0.7 to 1 .2 Langleys/minute. Using
the meter at your location, you can esti¬
mate how much solar energy is avail¬
able for conversion.

The radiometer circuit is shown sche-

RED

rxjpci

Ml/£

0-50mA^

Rlf

o.5ii,i%:

BLK

PARTS LIST

Ml — 0 to 50-mA dc milliammeter (Calectro
Dl-914)

PCI — Silicon photovoltaic solar cell (Calectro
J4-800 or Herback & Rademan TM 20K
187)

R! — 0.5-ohm, 1% resistor (see text)

Misc. — Suitable enclosure (Calectro H4-722
or equivalent), lug-type terminal strip,
hookup wire, 30-gauge enamelled copper
magnet wire, airplane cement or dope, gen¬
eral-purpose adhesive, machine hardware,
solder, etc.

Fig . 1. The solar cell causes a current to flow through the meter

matically in Fig. 1 . Current from photo¬
voltaic (solar) cell PCI flows through
Ml, a 0 to 50-mA meter, and shunt re¬
sistor fll. This resistor, consisting of a
length of 30-gauge magnet wire wound
on the body of a 2-watt, 1 -megohm car¬
bon resistor, bypasses some of the cur¬
rent around the meter, thereby expand¬
ing the range of light intensity to which
the meter will respond. A new meter
face calibrated in Langleys per minute is
applied over the old one for direct Insola¬
tion readout. Note that the prototype
was calibrated only for the parts speci¬
fied. Do not substitute any others or the
accuracy might be adversely affected.
However, you should have no problem
finding the parts listed because they
were chosen for their availability.

Construction. Begin by carefully re¬
moving the cover of meter Ml. The cov¬
er should snap off. Remove the two

the top of the enclosure to line up with
those in the photocell box. Replace the
foam padding and feed the output leads
of the solar cell through the small plastic
box into the project enclosure. Center
the solar cell — blue side up — making
sure it is level. Then close the transpar¬
ent lid of the box. Glue the bottom of the
box to the top of the enclosure, making
sure that it is centered and that the cell
leads pass freely into the case.

Mount a lug-type terminal strip on the
left inside wall of the enclosure.

You now need a 0.5-ohm, 1% resistor.
If you can find a commercial component,
you can use it. If not, you can make one
yourself. Prepare a 57-inch (144.8-cm)
length of 30-gauge enamel-covered
copper magnet wire, scraping the insu¬
lation from both ends so the wire can be
soldered. Then solder one end to a 2-
watt, 1 -megohm carbon resistor. (Actu¬

cell leads to the lugs observing proper
polarity. The red lead from the cell is
positive and should be connected to the
lug holding the wire attached to the +
terminal of the meter. Secure the lug
connections by soldering them. Reas¬
semble the enclosure by attaching the
front panel to the enclosure body, secur¬
ing it with the hardware provided.

Checkout and Use. The solar radi¬
ometer is now complete and ready for
testing. Position the project near an in¬
candescent lamp. The meter needle
should move upscale. If it deflects down¬
ward, the meter leads are reversed.

Using the radiometer is easier than
using a light meter. To measure the
peak solar radiation at a particular mo¬
ment, aim the cell directly at the sun and
record the maximum reading. This value
represents the energy one square centi¬
meter of a solar panel would receive if it
were pointed directly at the sun. But very
few solar panels are built to track the
sun — most are pointed south and tilted
upward at an angle approximately 10°
greater than the local latitude. By posi¬
tioning the radiometer in this manner,
you can measure how much solar ener¬
gy a panel would receive in practice.

To calculate the total energy reaching
this type of installation over the course
of a day, mount the radiometer on the
top surface of the panel. Take meter
readings frequently throughout the day.

Plot the radiometer readings (L) ver¬
sus time (t) on Cartesian graph paper.
The L axis should be scaled with 0.1-
Langley/minute increments, and the t
axis should have 10-minute increments.

small Phillips head screws that hold the
face plate in place. Cut out the new
scale shown in Fig. 2 and cement it over
the old scale using a general-purpose
adhesive. Then carefully reattach the
plate (after the adhesive has set) to the
meter body, securing it with the two
small screws. Snap the meter cover
back on the meter assembly, making
sure to position the cover’s zero-adjust
screw in the thin metal slot on the meter

Fig . 2 . Cut out this
scale for the meter
and attach it to
the meter faceplate.

movement. Fashion a 1.75-inch (4.4-

cm) diameter mounting hole on the cen¬
ter of an appropriate enclosure’s face
plate and mount the meter in it.

Remove the solar cell and padding
from the small plastic box it comes in
and drill two small holes in the black bot¬
tom of the box. Position the holes to
allow the leads from the solar cell to
pass directly through the box when the
cell is centered in it. Then center the
box — black side down — on top of the en¬
closure (see photo). Drill two holes on

ally, any 2-watt, carbon resistor greater
than or equal to 100,000 ohms is suit¬
able.) Coil the wire around the body of
the resistor and solder the free end to
the other side of the resistor. Coat the
wire with model airplane dope or glue to
hold it in place.

When the dope is dry, attach the re¬
sistor leads to two lugs of the terminal
strip. Connect short lengths of hookup
wire from both sides of the resistor to the
meter terminals. Then attach the solar

If these scaling factors are used, one
block on the graph paper represents one
calorie per square centimeter. To deter¬
mine the amount of energy per square
centimeter that reached the solar panel
in the course of the day, you must “inte¬
grate” the curve by finding the total area
under it. The simplest way to do this is to
count the number of boxes and fractions
of boxes lying under the curve. This total
will be all the energy falling on one
square centimeter of the panel for that

POPULAR ELECTRONICS

day. To find out how much energy was
available to the entire panel, multiply the
area under the curve (in calories/cm2)
by the total area of your solar panel (in
cm2).

It should be stressed that the total
available energy is not the total energy
output of the solar energy converter. So¬
lar heating panels are never 100% effi¬
cient, but average 70 to 80% for flat-
plate water heaters. Any good physics
or solar energy book will outline steps to
measure actual efficiency. Remember
that, due to variations in components
and measurement techniques, your
measurements will be accurate to about
±5% at best. This is fine, however, for
“backyard experiments.”

Other Uses. There are several other
applications for this project. It can be
used as a transmittance/reflectance
meter to measure the percentage of so¬
lar energy transmitted or reflected by a
particular material or surface. The radi¬
ometer can also be used as a pyranom-
eter to measure radiation from the sky.
Simply point the solar cell straight up.
Readings taken over the course of the
day should now correspond with stand¬
ard meteorological data.

Relative efficiencies of lamps and oth¬
er light sources can be determined. You
can easily measure the electric power
input (or use manufacturer’s data), and
the radiated output power can be cal¬
culated using this relationship:

1 Langley 0.0698 watt
minute ~~ cm2

From this data, efficiency (power out/
power in) can be obtained.

Another interesting experiment uses
the radiometer as an air pollution indica¬
tor. Record direct readings of solar ener¬
gy as the sun is setting. On a pollution-
free day, a plot of this data versus time
should fall off smoothly as the length of
the sun’s rays’ path through the atmo¬
sphere increases. However, if a large
cloud of smog is hanging over a city to
the west, the readings might dip sharply
as the sun goes “behind” the smog
cloud. This is only a relative indication,
but comparisons over a period of days
might point to some sort of pattern. By
determining the angle above the horizon
at which the readings start to dip and the
distance to the city, you should be able
to calculate the approximate height of
the smog cloud by trigonometry. The
technique will also be applicable looking
east in the morning.

With a little imagination, you will sure¬
ly find other applications for this useful
project. O

DECEMBER 1976

~ Our

Synergistic

System

We make one of the finest tone arms in the world
(ask the editors of AUDIO magazine) but how well
it performs is dependent-at least partly- -

on the cartridge.

We also make one of the finest phono
cartridges in the world (ask almost
anyone about the AT20SLa) but how
well it can perform is governed at
least in part by the tone arm.

But even the finest combination
of cartridge/tone arm is influenced
by how clean the records may be..,
and how clean the stylus is. So we
have both a superb manual
and automatic record cleaner,
and a fine stylus cleaner.

And of course the whole system
works best only if it is free from such
things as acoustic or mechanical
feedback (especially with a cartridge
having subsonic capabilities like
ours), and excessive cable capacity.
We solve these problems neatly
and effectively with our
I AT- 605 Audio Insulator and

^ AT -61 0 Low Capacity

cable set.

Finally, we also make one of the
finest headphones in the world
(ask Len Feldman) our incredible j
AT -706 that makes all the care
that went before audibly '

worthwhile.

Any one of these components in your — ^

system can assure you of the very finest
standard of performance— from that component.

All of them together provide an unparalleled listening

Start anywhere in our system. You’ll soon find that as
you add Audio-Technica products, you multiply enjoyment.

(®audio-technica

IN NOVATION □ PRECISION □ INTEGRITY

AUDIO-TECHNICA U.S., INC., Dept. 126P, 33 Shiawassee Avenue, Falrlawn, Ohio 44313

HOWTO

PREDICT
CB RADIO
RAIOE

Antenna height, ERP, noise, and sensitivity
by ira s. gerson influence effective communication range.

OF MAJOR concern to most CB’ers
is the effective working range of
their communications equipment. Here
we explore a method of accurately pre¬
dicting range for base-to-mobile and
mobile-to-base radio links. Since CB
communications are limited by FCC re¬
gulations to 1 50 miles, we’ll focus our at¬
tention on ground wave rather than sky
wave signals.

Radiation from an antenna follows two
routes. One component travels parallel
to the earth’s surface. This is called the
ground wave. The other component
goes up into the sky, sometimes reflect¬
ed back by the ionosphere as “skip.” Al¬
though the range of skip signals can be
hundreds or thousands of miles, skip is
a transient phenomenon at best. Apart
from legal considerations, skip is pres¬
ently very rare because solar activity is
low, and will remain so for at least a few
years in the future.

Range Predictions. By limiting our
consideration to the ground wave, we
can arrive at a good estimate of the con¬
sistent range of a two-way radio system.
To come up with a meaningful result,
three basic quantities must be deter-
48

mined. They are defined as follows:

•ERP or effective radiated power— a
function of the r-f power output of the
transmitter, losses in the connectors and
transmission line, and antenna gain or
loss.

•Propagation loss — a function of the
heights of the two antennas, the dis¬
tance between them, and the terrain
loss for a given communications reliabil¬
ity above the median of 50% level.

•Receiver Environmental Loss— a
function of ambient noise in the vicinity
of the receiver, the receiver antenna
gain or loss, losses in connectors and
the transmission line, and the receiver’s
signal plus noise to noise ratio (S+N/N).

A convenient way to relate these three
quantities is with the graph shown in Fig.
1 . It is called a “Power Level Diagram.”
To use the diagram, simply find the pow¬
er level which is equivalent to your base
or mobile receiver's sensitivity in dBm or
microvolts. Then add a quantity called
the “J factor” and the propagation
losses (both of these will be thoroughly
developed). You can now determine t he
required ERP for the distance covered,
or the distance that can be reached for a
given ERP.

The J Factor. This is the difference
between the receiver’s sensitivity and
the signal level required for effective
communications. Studies indicate that a
signal level greater than the receiver’s
sensitivity rating is necessary for good
results. This signal level, Va, is principal¬
ly influenced by the ambient r-f noise in
the vicinity of the receiver. (Note that the
noise considered in an S-fN/N mea¬
surement is generated by the receiver it¬
self.) However, receiving antenna,
transmission line, and connector losses
will also affect the value of Va.

To determine the J factor, you must
either assume a value of ambient noise
in the service area of the base or mobile
transceiver or measure the noise level
with the unit’s signal strength meter. If
you are going to estimate the noise lev¬
el, you can use the following generaliza¬
tions: IpV for rural areas; 3 to 10 pV in
the suburbs; and 10 to 40 pV for most
urban areas.

On the other hand, the transceiver’s S
meter can be used. Keep the squelch
wide open, and note the meter reading
on a clear channel. Then check the op¬
erations manual of the transceiver, a
product test report, or write the manu-
P0PULAR ELECTRONICS

Fig. 2. Plot of Va versus ambient r-f noise.

facturer, requesting the actual signal
strengths in microvolts that correspond
to meter readings from SI through S9.

Once the value of r-f noise has been
determined, refer to the graph of Fig. 2.
Note that two curves have been plotted.
These correspond to receiver sensitivi¬
ties of 0.3 piV and 1 piV, which are the
approximate lower and upper limits for
state-of-the-art transceivers. Find the
proper value of noise on the horizontal
axis, and then determine the value of
Va. This value is then inserted in the fol¬
lowing formula:

J factor (dB) = 20 logi o (Va/receiver
sensitivity).

Propagation Losses. These relate
the ERP of the transmitting portion of the
link to the fraction of the output recover¬
able at the receiver. Here, propagation
losses over plane (flat) earth were cal¬
culated based on a base antenna height
of 60 feet (18.3 m) above average
ground level and a mobile antenna
height of ten feet (3.05 m). One very im¬
portant assumption here is that the in¬
tervening terrain is relatively flat with no
high hills, deep valleys, and a few man¬
made obstructions. Also, additional
losses of 4 dB are added to achieve a
greater margin of reliability.

In many areas, the terrain is hardly
ideal or flat. Accordingly, you can expect
to have range decreased or increased,
depending on whether the mobile is at
one point on top of a steep hill or in a val¬
ley, or near the base of a tall building.

There are other factors besides contour
that can make the terrain non-ideal. One
such factor is ground resistivity. Al¬
though the plane earth is described as a
flat, perfectly conducting surface, real
earth acts as a resistance. It has been
found that at frequencies near 30 MHz,
vertically polarized signals passing over
“good” soil (clay, loam, marsh or
swamp) are affected by the contour of
the surface and soil resistivity if the an¬

tenna heights are less than 30 feet (9.13
m) above average ground level.

Mobile antennas fall into this catego¬
ry, and as a result a decrease in propa¬
gation loss of as much as 10 dB can oc¬
cur. In addition to affecting propagation,
earth ground can also influence the
impedance of a mobile antenna and
thus affect the efficiency figure of the an¬
tenna system.

Fig. 1. Power level diagram shows relation between
ERPf propagation losses, J factor and sensitivity.

DECEMBER 1976

Range Predictions. Having deter¬
mined the J factor, you can now proceed
to estimate the range for a given com¬
munications link. Referring to the Power
Level Diagram in Fig. 1, the “padding”
effect of the J factor is readily apparent.
In Fig. 2, the influence of the J factor on
Va for given noise levels and receiver
sensitivities can also be seen. The J fac¬
tor and propagation losses have been
considered in setting up Fig. 3, which re¬
lates ERP to distance. To simplify its
use, a family of curves was plotted for
the two receiver sensitivities (0.3 and 1
p,V for 10 dB S+N/N) and for four levels
of r-f noise (0.3, 1 , 3, and 10 jjlV).

Suppose that omnidirectional cover¬
age from a base station with an antenna
of 60 feet (1 8.3 m) is desired. Assume
that the ERP is four watts or 36 dBm.
(This condition occurs when the trans¬
ceiver r-f power output is four watts— the
legal limit — and when antenna gain ex¬
actly compensates for connector and
transmission line losses.) Further as¬
sume that the service area is suburban
with a 3 -p,V noise level, and that the re-

The

POLY 88
Microcomputer
System

The POLY 88 Microcomputer System
brings to the user, in one compact
package, the capability of developing
programs and hardware as well as
enjoying the interaction with computers.

The POLY 88 System uses a video
monitor for display, a keyboard for input
and cassette tape for storage. The
system will also connect to a hard-copy
terminal. Poly 88 hardware consists of an
8080 based CPU circuit card with on¬
board memory and I/O, video display
circuit card with keyboard input port
and graphics capability, and mini-cards
that connect to the CPU board via
ribbon cable for cassette or serial
interface.

The Firmware Monitor is integral to the
POLY 88 System. This 1024 byte
program in ROM allows the user to
display data on a TV screen, enter data
into memory using a keyboard, read and
dump data to the cassette interface in
Kansas City format, and single step
through a program while displaying the
contents of each of the 8080s internal
registers.

Prices: Basic kit including chassis, CPU
and video cards — $595 , $795
assembled. Cassette option — $90 kit
and $125 assembled. 8K of RAM —$300
in kit form or $385 assembled.

Dealers: This system will sell itself.

All prices and specifications subject to change without
notice. Prices are USA only. California residents add
6% sales tax. Prepaid orders shipped postpaid.
BankAmericard and Master Charge accepted.

PolyMorphic

Systems

737 S. Kellogg Avenue, Goleta, Ca. 93017
(805) 967-2351

Fig. 3. Effective radiated power versus distance for
two sensitivities and various r-f noise levels .

ceiver sensitivity is 1 p,V for 10 dB
S+N/N. Here’s how the range is pre¬
dicted.

Locate the 36-dBm line and proceed
across until the 3-pA/ curve is reached.
Then read the corresponding distance.
In this case, it is five miles (8 km). Of
course, you can work backwards and
determine how much ERP is required for
5-mile coverage. Proceed down the 5-
mile line until the 3-pA/ curve is reached,
and then read the corresponding ERP
value (36 dBm or four watts).

Further Comments. Mobile anten¬
nas are less efficient than base anten¬
nas, so it is obvious that mobile range
will be more limited. It will typically be
three miles (1 .8 km). From Figs. 2 and 3,
it can be concluded that, for ambient r-f
noise levels above 1 p.V (which is usual¬
ly the case on the Citizens Band), an in¬
crease in receiver sensitivity of 33314% ,
say, from 1 pA/ to 0.3 pA/ for 10 dB
S+N/N, reduces the required ERP only
10%. Only in extremely quiet r-f environ¬
ments (under 0.5 pA/), which probably
don’t exist on the Citizens Band in even
the most rural areas, will there be any
significant reduction in ERP required for
a given distance.

In other words, a sensitivity of 1 pA/ for
10 dB S+N/N appears to be adequate
for most applications. However, whether
an S+ N/N of 1 0 dB is sufficient for good
intelligibility is altogether another ques¬
tion. If a more sensitive receiver (0.3 p,V
for 10 dB S+N/N) is used, providing a
better ratio, say, 15 dB at 1 pA/, the oper¬

ator has a definite advantage in terms of
audio quality or intelligibility.

Another area for consideration is the
relative merit of a beam over an omnidi¬
rectional antenna. Unquestionably, a
beam will allow you to reduce interfer¬
ence (and thereby improve intelligibility)
from stations in other directions than the
desired station. But let’s limit this discus¬
sion to the relative merit in terms of
range. The maximum permissible height
for an omni is 60 feet (18.3 m) above
ground, natural formation, or man-made
structure. For a beam, the maximum
allowable height is 20 feet (6.1 m). It can
be shown that if the antenna height is
halved, you will require 6 dB more power
to reach the same distance.

Therefore, if you now have or are
planning an omnidirectional antenna
with unity gain mounted at 60 feet (18.3
m), and want to weigh the advantages of
installing a high-gain beam and rotor
system, consider this. You must subtract
6 dB from the beam’s gain because of its
lower height. In terms of the graph of
Fig. 3, start at 36 dBm ERP, add the
beam’s gain, subtract 6 dB, and proceed
across the graph until the appropriate r-f
noise curve is reached. Then note the
predicted range. If the gain of the beam
is 6 dB, the range will be the same for
the omni and the beam. If gains of 9 dB
or more are not available, or if the beam
will not be mounted considerably higher
than 30 feet (9.15 m) above average
ground level, the omnidirectional anten¬
na at 60 feet (18.3 m) above ground lev¬
el is the better choice. O

POPULAR ELECTRONICS

50 CIRCLE NO. 52 ON FREE INFORMATION CARD

Popular Electronic^

fcs? i ^ ft

Digital techniques play a leading role in electronics to¬
day. Switching, coding and logic function methods are
not difficult to grasp . And equally important, they make
it possible to create many interesting electronics circuit
designs. In this special supplement, many of these con¬

cepts are illustrated, including projects for a digital auto
fuel gauge and a shirt-pocket digital stopwatch. In addi¬
tion, the first article gives many helpful hints on how the
electronics hobbyist should go about choosing a mi¬
crocomputer from the many available today.

How to Select
a Hobbyist
Microcomputer

DECIDING which microcomputer to
buy is quite a challenge. Not only
are there several dozen on the market,
but they’re available in a wide range of
prices, with a variety of features and per¬
ipherals, and with several different
MPU’s (microprocessor units), such as
the 8080, 6800, 6502, F8 and 6100,
among others.

One of the easiest ways to narrow
down your choice of a microcomputer is
to decide which basic type is best for
your own use. To do this requires a
breakdown of microcomputer types, as
in the following paragraphs.

1. Box With. The best-known type
of microcomputer looks very much like a
minicomputer: a box with a bunch of
switches and lights on the front panel.
Two hobby computers of this type are
the MITS Altair 8800b and the Imsai
8080. This microcomputer type is the
most widely used among hobbyists, with
the widest choice of peripherals and
memory expansion boards.

2. Box Without. The second type of
computer is also a box, but with a bare

BY STEPHEN B. GRAY
Senior Editor

Type 1:

MITSAltair 8800b

Type 1:
Imsai 8080

Type 2:

Southwest Technical 6800

Type 2:

Poly Morphia Poly -8 8

Ty pe 3:

Microcomputer Assoc, JOLT

minimum of switches and lights. An ex¬
ample is Southwest Technical Products1
6800, which has only two switches, for
power and reset. Only the power switch
has a light.

There are two main differences be¬
tween Type 1 and Type 2 computers.
First, with a Type 1, you can load short
programs and operate the computer
manually, reading the results on the
LED display. Obviously, you can’t do
this with a Type 2 machine. The second
difference is in loaders. When you turn
on any microcomputer, you can’t put a
program into memory until a bootstrap
loader is inserted first. This acts as a set
of signs to guide the program to the right
places in memory. With most of the
Type 1 computers, you have to load the
bootstrap instructions by hand, using the
front-panel switches. With most of the
Type 2 computers, which have stored
loaders, all you do is press reset and
the loader is inserted automatically.

However, just because a microcom¬
puter has a full set of switches and lights
isn’t always a sign that the loader must
be inserted by hand. The MITS 680b is a
good example of a micro with switches,
lights, and a bootstrap loader in perma¬
nent memory which doesn’t “drop out”
when the power is turned off.

Note too, that not all micros have the
same internal expansion capability. This
sometimes accounts for differences in
size and, naturally, influences price too.

3. PC Board. The third main type of
microcomputer consists of a printed-cir¬
cuit board without input or output. These
were first introduced for use in commer¬
cial products, or for engineering evalua¬
tion, and many are still sold for such pur¬
poses. Several recent ones are being
sold mainly to hobbyists. The best-
known of Type 3 are the Jolt and SC/MP.

All the computers described up to this
point have neither separate input nor
output. So unless you enjoy loading pro¬
grams via front-panel switches (if your
microcomputer has them) and reading
out the program results from the front-
panel lights, you’ll need some more
hardware. This means a keyboard for
putting data into the computer, and a
more sophisticated readout for checking
that the program is correct and for read¬
ing the results. There is already a wide
variety of keyboard terminals available,
and the most common readout today is
a TV screen.

4. All-On-One-Board. For those
who want a complete computer with less
sophisticated inputs and outputs than

teletypewriter and video monitor, there
are many everything-on-one-board mi¬
crocomputers. This type includes a
small keyboard and some form of read¬
out. The readout is sometimes individual
LED’s, but is usually segmented al¬
phanumeric display. The KIM-1 is the
best known of these, although several
others are coming up fast. Two units
come with a case, the Infinite UC 1800
and the Hamilton/Avnet Pacer. They
have built-in power supplies, whereas
most of the others don’t.

Just about the least expensive Type 4
microcomputer for the hobbyist who
wants to learn the basics is the Elf, fea¬
tured as a construction project in the Au¬
gust and September 1976 issues of
Popular Electronics. This hardware
and software trainer, with RCA COS-
MAC MPU, toggle-switch input, hex LED
display, 256 bytes of RAM, four input
lines, and a latched output line, costs
about $80 to build. Memory is expand¬
able at minimum cost.

Nearly all the computers of this type
are on a single pc board; two exceptions
are the Mike 3 and Mike 8, from Martin
Research. Each is a stack of several
boards, separated by spacers, with the
keyboard and display on the console
board at the top, CPU on a second
board, memory on a third, etc. This mod¬
ular approach permits using different
CPU boards, either for the 8080A MPU,
Z-80, or 8008.

The keyboard almost always has 16
hex keys for entering programs in ma¬
chine language plus various control
keys. These boards are popular among
people who want to learn what comput¬
ers are all about, at minimum cost. For
those who want to go further, more
memory can be added, as can be peri¬
pherals such as a full keyboard and/or a
printer, to start with.

5. AKI-lwOne Box. Another type of
computer that doesn’t require buying a
keyboard or TV set has a built-in key¬
board and CRT, such as the various
models of the Sphere. Although this type
of computer is expensive, it does have
everything you’d need for almost any
type of programming. However, you are
locked into the integrated input/output
system much as you are for an FM tuner
when it’s built into an FM receiver. A
printed output can be added on, as it can
to almost any hobby computer. The cost
of a simple printer has decreased sub¬
stantially. For example, Southwest
Technical offers one in kit form for $250,
and Electronic Products Associates has
an assembled printer for $450.

POPULAR ELECTRONICS

Among the computers of this type, the
intecoior 8001 , with an 8-color CRT, is
unique. This adds an extra dimension to
graphics and to just about anything you
want to put on the screen.

Intelligent Terminals. A step up
from most hobby terminals, which can
be used only as input/output devices, is
the intelligent terminal. With one of
these, you can write, edit and store pro¬
grams for transmission to a larger com¬
puter directly, or to a time-sharing com¬
puter over a telephone line (using a mo¬
dem device).

Any hobby computer with a keyboard,
RS-232 or 20-mA current-loop interface,
and enough memory can be used as an
intelligent terminal, of course. All you
need are the right programs. The SOL
terminal from Processor Technology
provides these programs in the form of
pre-programmed PROM’s, called “Per¬
sonality Modules,” at three levels.

One module allows simple terminal
operations. A second-level module
makes SOL an editing terminal. The top-
level module transforms it into an intelli¬
gent terminal as well as a stand-alone
computer.

Programming. An important factor
in choosing a hobby micro is to decide at
which level you want to program. How
much memory your computer has will
determine its price and also what kind of
programming language you can use.

With only a few hundred bytes of
memory, you’ll usually be restricted to
programming in machine language, or to
short programs in assembly language.
Some people enjoy working in machine
language, down at the bit level, using in¬
structions such as 00111010, which is
the 8080 code for “load the accumulator
with the contents of the specified memo¬
ry address.”

But working with machine language
may be boring to all but real “computer
freaks.” Also, you can easily make mis¬
takes that aren’t at all quickly apparent
when working with only zeroes and
ones. With a little more memory, though,
you can program in assembly language.
In order to do this, you must load an as¬
sembler into your computer’s memory.
This is a program that translates the as¬
sembly-language instructions, such as
LDA, into machine language, in this
case, 00111010.

In assembly language, you use mne¬
monic names for program instructions;
these are easy-to-remember abbrevia¬
tions, such as LDA for “load accumula¬
tor” and MOV for “move the contents of
the accumulator to register B.” To add

one number to another in 8080 assem¬
bly language takes eleven steps, includ¬
ing five mnemonics and three pairs of
address codes. Address codes are in
pairs because addresses take up two
bytes ; that is, groups of 8 bits. (An 8080
machine can address 216 memory loca¬
tions.)

The program for adding two numbers
consists of these steps: load the ac¬
cumulator with the number to be found
at, say, memory address 128. Then take
what’s in the accumulator and move it to
register B. Next, load the accumulator
with the number to be found at address
1 29, and add the contents of register B
to what’s in the accumulator. Take the
sum that's now in the accumulator, and
store it at address 130. If you’ve previ¬
ously stored numbers at addresses 128
and 129, this program will add them
together and put the sum in 130. Actual¬
ly, you can use any memory addresses
you want, instead of 128, 129 and 130,
as long as you don’t select an address
that’s higher than the maximum address
in your system.

If you’d rather write programs with
mnemonics such as LDA, MOV and
STA, then you need, as previously not¬
ed, an assembler program, which is also
stored in memory along with your own
program. For example, the MITS Altair
8800b assembler takes up 5500 bytes of
memory, so if you’re going to be writing
programs of any real length, you’ll need
at least 8k bytes of memory.

But suppose you’re not really interest¬
ed in programming for programming’s
sake, but rather in what the program will
do for you. If so, then you might prefer
BASIC, a high-level language that will
do in a single instruction, LET C = A
+B, what requires eleven assembly-lan¬
guage instructions to do. That single BA¬
SIC instruction will store the sum of A
and B in memory location C, which is de¬
termined by the BASIC interpreter all by
itself, thus taking care of much
housekeeping. Should you want to show
the answer on your TV screen, or print it
out, simply write PRINT C. Or you can
combine both steps by writing a single
BASIC instruction, PRINT A+B.

Just about all high-level-language
programs written for hobby computers
are in BASIC (there are several varieties
of BASIC, each with minor differences).
You can get several BASIC interpreters
for some computers, requiring 4k, 8k or
1 2k bytes of memory. The 8k and 1 2k
versions offer more features than the 4k
BASIC. The 8k BASIC interpreter, which
turns LET C = A+B into machine lan¬
guage, takes up 5.7k bytes of memory in

Type 3:

HAL MCEM-8080

Type 4:

MOS Technology KIM-1

Type 4:

Intersil Intercept Jr.

Type 5:
Sphere 310

Type 5:

Intelligent Sys. Intecoior 8001

DECEMBER 1976

the Altai r 8800b, for example. MITS spe¬
cifies it as requiring 8k bytes of memory
so that you’ll have 2.3k bytes for your
own use in writing programs. Incidental¬
ly, although many serious computer
hobbyists will be satisfied with 8k or 1 6k
of memory, many hobby computers can
be expanded to 65k.

Hobbyist Bus. The MITS Altair
8800 microcomputer was the first to be
sold in large volume, and set a bus
standard that some other micro manu¬
facturers have followed. This standard i^
based on the 100-pin bus, to which all
the Altair 8800 boards are connected in
common. Consequently, many other
manufacturers of CPU boards, memory
boards, and peripheral boards have tail¬
ored their designs so they will plug into
the Altair 8800, and also into the busses
of several other computers that use the
Altair bus structure, including the Imsai
8080, the PolyMorphic Poly-88 and
Processor Technology’s SOL. As a re¬
sult, there are more boards for CPU and
memory, and for peripherals such as
printers, disk drives, graphics devices,

cassette memory, etc., available to own¬
ers of computers using this bus.

There are other bus lines, of course.
For example, the Southwest Technical
6800 computer utilizes a different bus,
with a growing number of boards for it.

Price. Of the five basic types of hob¬
by computers, the cheapest is the pc-
board-only, with which you need a pow¬
er supply, an input, and an output. The
complete-computer-on-a-board follows,
and usually requires the addition of only
a power supply. Next is a box-type com¬
puter with which you’ll need input and
output peripherals. With a box^with-CRT
type, which gives you the most equip¬
ment at a minimum cost, on a one-shot
basis, you already have the peripherals,
unless you also want a printed output.

Let’s look at what it costs to buy a mi¬
crocomputer with enough memory for
the various levels of programming, tak¬
ing into consideration several of the
best-selling micros. The basic computer,
without memory can range from $21 2 to
$840 in kit form, $500 to $1 100 assem¬
bled. These wide ranges are due to

some of the computers being full-
featured models, others being “bare-
bones” types. Not many Ik memory
boards are being offered any more; they
used to be about $120 kit, $160 assem¬
bled. Using just a basic 8-bit computer
and 1 k of memory, you could write pro¬
grams containing up to about 500 in¬
structions, if you don’t mind flipping
switches for hours and hours.

Stepping up to assembly language,
you’ll need two 4k memory boards, each
of which run from $125 to $167 kit, $279
to $325 assembled. If you buy the Altair
8800b and the two 4k boards at the
same time, you get a “software pack¬
age” for $75, which includes the assem¬
bler and several other programs. The
Southwest Technical 6800 editor/
assembler package is $14.95.

You’ll need some sort of input/output,
of course. To connect your computer to
your TV set requires an interface that
can cost from $40 to $148 kit, $60 to
$180 assembled. For keyboard input,
you may be able to use the same inter¬
face if it can handle two serial I/O de¬
vices. You’ll also need a keyboard termi-

bfrcRpccJ

All-On-One-Board

Applied Microtechnology AMT 2650
Comp-Sultants Micro-440
COSMAC Elf
EBKA 6502 Familiarizor
E&L Mini-Micro Designer
E PA-68

Hamilton/Avnet Pacer
Infinite UC 1800
Intersil Intercept Jr.

Martin Research Mike 3, Mike 8
Monolithic Systems MSC 8080+
MOS Technology KIM-1

PC Board

Apple Computer Apple-1
Burkeshire Systems EPIC 2
HAL MCEM-8080
Microcomputer Assoc. JOLT
National Semiconductor SC/MP
Pronetics PS-810

POPULAR ELECTRONICS

nal, such as a Model 33 Teletype. This,
however, is expensive, costing between
$769 and $1500 new, depending on
what features you select. With an
ASR33, you can enter a program from
either the keyboard or punched paper
tape. Or you could get a hobby unit,
such as Southwest Technical’s CT-1 024
terminal. With this, the program is en¬
tered via the keyboard. The CT-1 024 kit,
less cabinet and power supply, is $175;
there are various options available.

Programs can be entered into the
computer much faster by using a cas¬
sette. To enter the 8k BASIC interpreter
into the Altair 8800b takes 12 minutes
from paper tape, 4 minutes from cas¬
sette. Typical cassette interfaces range
from $35 to $138 kit, $65 to $1 95 wired.
You can buy a 4k BASIC interpreter for
$4 to $60 depending on manufacturer.
The 8k BASIC interpreter ranges in price
from $8 to $75.

Which to Pick? A major question to
answer is: will you be satisfied with pro¬
gramming in assembly language, or do
you want to program in BASIC? If you’re

sure you’ll be happy with assembly lan¬
guage, you have two types of computers
to choose from. The least expensive is
the all-on-one-board computer, Type 4,
such as the KIM-1 or 6502 Familiarizor,
where the only extra to buy is a power
supply except for a couple that have it
built in. The other choice is Type 3, the
pc board with no I/O, such as the SC/
MP. To use one of these, you’ll need a
power supply, keyboard, and some sort
of output, either a printer or a TV receiv¬
er or video monitor.

If you’re more interested in programs
than in computers, and want BASIC, you
have three choices. The Type 1 comput¬
ers, including the Altair 8800b and Imsai
8080, require interfaces and peripherals
for input and output, as do the Type 2
machines, such as Southwest 6800 and
Poly-88. You can add these at any time.
You’ll need no additional hardware if you
buy a Type 5 computer, which has both
CRT and keyboard.

Summarizing, you must decide what
you plan to do with the microcomputer
now and in the future, as well as what
your bankbook can tolerate.

Are you determined to be an experi¬
menter, more interested in hardware
and/or learning the fundamentals of
computers? If so, a Type 3 or 4 unit
might be your best bet.

If you’re more interested in “talking” to
your computer and getting results easier
and faster, but wish to add peripherals of
your own choice at some future time, a
Type 1 or 2 could be the way to go.

Should you want an all-in-one type of
micro, with peripherals already incorpo¬
rated, then perhaps a Type 5 should be
considered.

There are other factors to weigh, of
course, including language availability
(do they have assembler or BASIC?),
reputation of the computer manufacturer
(how good are their computers and how
long will they stay in business?), wheth¬
er or not you plan to join a computer club
for sharing ideas and trading information
on software, and so on.

More Help. In addition to asking a
manufacturer to send information on his
microcomputer for performance details
(see address listing), there are many

Box With

ETC-1000
Imsai 8080
MITS Altair 680b
MITS Altair 8800b
M&R Astral 2000
PCM-12

AIMn-One-Box

Inteligent Systems
Intecolor 8001
Mikra-D BASIC-8
Sphere 300 Series

Box Without

Digital Group System
OSI Challenger
PolyMorphic Poly-88
Processor Technology SOL
Southwest Technical 6800
Veras Systems F8
Wave Mate Jupiter II

DECEMBER 1976

other ways to help you decide which to
buy. There are over 90 computer clubs,
many with membership in the hundreds,
where you can talk with people who are
using various hobby computers. Dozens
of computer stores around the country
will show you how their products work,

and answer your questions in detail.
Magazines and club newsletters devot¬
ed to the computer hobbyist are also ex¬
cellent sources of information. And if you
get to a hobby-computer convention,
such as the ones that were held in New
Jersey (Trenton and Atlantic City), you

can check out dozens of computers and
peripherals in a single day, as well as lis¬
ten to talks about hardware, software
and applications.

Whatever choice you make, you’ll find
yourself in a new, exciting field that will
add to your knowledge and fun. O

DIRECTORY OF MICROCOMPUTER AND PERIPHERAL MANUFACTURERS

Apple Computer Co.

770 Welch Rd., Palo Alto, CA 94304

Applied Microtechnology

100 N. Winchester Blvd., Santa Clara, CA 95050

Burkeshire Systems

P.0. Box 512, Mountain View, CA 94040

Comp-Sultants

P.0. Box 101 6. Huntsville, AL 35800

Cromemco

One First St., Los Altos, CA 94022

Digital Group, The

Box 6528, Denver CO 80206

Dutronics

P.0. Box 91 60, Stockton. CA 95208

E&L instruments, Inc.

61 First St., Derby, CN 0641 7
EBKA Industries, Inc.

6920 Melrose Lane, Oklahoma City, OK 73127

Electronic Control Technology

P.O. Box 6, Union, NJ 07083

Electronics Products Associates, Inc.

1 1 57 Vega St., San Diego, CA 921 1 0

Electronic Tool Co.

4736 El Segundo Blvd., Hawthorne, CA 90250

Gnat Computers

6869 Balboa Ave., Unit C, San Diego, CA 921 23

God bout Electronics

Box 2355, Oakland Airport, CA 94614

Hal Communications Corp.

P.O. Box 365, Urbana, IL 61 801

Hamilton/ Avnet Electronics

1 0950 West Washington Blvd.. Culver City, CA 90230

IMS Associates, Inc.

14860 Wicks Blvd., San Leandro. CA 94577

Infinite Inc.

P.O. Box 906, Cape Canaveral, FL 32920

Intelligent Systems Corp.

4376 Ridgegate Dr., Duluth. GA 30136

Intersil, Inc.

10900 N. Tantau Ave., Cupertino, CA 95014

Lear Siegter Inc.

714 N. Brookhurst St., Anaheim, CA 92803

M&R Enterprises

P.O. Box Irflt, Sunnyvale, CA 94088

Martin Research

3336 Commercial Ave., Northbrook, IL 60062

Microcomputer Associates

2589 Scott Blvd , Santa Clara, CA 95050

Micro Peripherals, Inc.

P.O. Box 22101 , Salt Lake City, UT 84122

Mikra-D, Inc.

30 Main St., Ashland. MA01721

MITS

2450 Alamo SE, Albuquerque,. NM 87106

Monolithic Systems Corp.

1 4 Inverness Dr. East, Englewood, CO 801 10

Mos Technology, Inc.

950 Rittenhouse Rd., Norristown, PA 19401

National Multiplex Corp.

3474 Rand Ave., So. Plainfield, NJ 07080

National Semiconductor Corp.

2900 Semiconductor Dr., Santa Clara, CA 95051

Ohio Scientific Instruments

1 1 679 Hayden SL, Hiram, OH 44234

PCM Company

Box 21 5, San Ramon, CA 94583

PolyMorphic Systems

737 S. Kellogg, Goleta, CA 9301 7

Processor Technology
6200 Hollis St., Emeryville, CA 94608

Pronetics Corp.

P.O. Box 28582, Dallas. TX 75228

RCA Solid State Division

Box 3200, Somerville, N J 08876

Scientific Research Instruments Co.

P.O. Drawer 2096, Ashland, VA 23005

Southwest Technical Products Corp.

Box 32040, San Antonio, TX 78284

Sphere Corp.

P.O. Box 213, Bountiful, UT 84010

Tarbell Electronics

144 Miraleste Dr., #106, Miraleste, CA 90732

Vector Electronics Co.j Inc.

1 2460 Gladstone Ave., Sylmar, CA 91 342

Veras Systems

P.O. Box 74, Somerville, MA 021 43

Wave Mate

101 5 W. 1 90th St., Gardena, CA 90248

Wintek Corp.

902 N. 9th St., Lafayette, IN 47904

Digit

Probe

EVER SEE a logic probe that was so
compact that it could fit over the tip
of your finger? Although there is such a
device (see photo), don’t look for It com¬
mercially — you have to make it yourself.
We call this ultra-compact little gem the
“Digit Probe,” mainly because in use it’s
like an extension of^your index finger.
Used in this manner, the Digit Probe
makes it easy to trace pulses around
crowded 1C assemblies and pc board foil
traces that all look alike.

As shown in the schematic diagrams,
the circuits for the Digit Probe are basic
56

BY LESLIE SOLOMON
Technical Editor

Compact, easy-to-use logic probe
fits your finger.

The Digit Probe fits on finger.

POPULAR ELECTRONICS

Use either a LED
readout or audible signal

hi/lo indicators. Circuit A provides a vi¬
sual indication of conditions existing in
the circuit under test via light-emitting di¬
ode LED1. Circuit B provides an audible
indication via the Mallory Sonalert ® Cir¬
cuit A is convenient for tracing pulses in
an operating system, while circuit B is
more convenient when you have to look
away from the system under test to
make equipment adjustments and can’t
monitor a LED.

All components (except the Sonalert)
in both circuits should be kept as small
as possible so that the assembled circuit
can be mounted on an ordinary plastic
guitar/banjo pick. Use a miniature gen¬
eral-purpose npn transistor for Q1 and

14-watt resistors for R1 and R2. Any size
of color discrete light emitting diode can
be used for LED1.

Construction. The Digit Probe circuit
mounts directly on the outer surface of
the guitar/banjo pick and is held in place
with quick-setting clear epoxy cement.
Assembly is very easy and non-critical,
but you will have to take care to keep the
physical layout as compact as possible.

Start construction by trimming both
leads of the two resistors to W (6.4 mm)
and bending the lead stubs into hooks.
Pre-tin the head of a straight pin with
solder and solder the head of the pin to
one lead of R1 . Solder the other lead of
R1 to the base lead of Q1. Solder the
cathode lead of LED1 to the collector
lead of Q1 and the anode lead to one
end of R2. Solder separate 36" {about
1 -m) lengths of small-diameter stranded
hookup wire to the free end of R2 and
the emitter lead of Q1, using red and
black insulation, respectively. Terminate
the free ends of the hookup wire with
miniature alligator clips. Finally, loosely
twist together the hookup wires.

If you’re planning to make the audible
version of the Digit Probe, eliminate R2
and LED1. Wire the circuit as described
above, locating the Sonalert about 10"
(25.4 cm) from the alligator clip end of
the twisted-pair power cable.

Liberally coat the area of the guitar/
banjo pick on which the Digit Probe cir¬
cuit is to mount with epoxy cement.
Press the circuit into the cement, orient¬
ing it as shown in the photo. Slip over
the projecting straight pin a length of
plastic sleeving, leaving about 14" to
3/i6" (3.2 to 4.8 mm) near the point of the
pin exposed. Coat the circuit with more
epoxy cement to assure a firm mechani¬
cal anchor. Then allow the cement to
cure for at least 24 hours before using
the probe.

In Use. Slip the Digit Probe over the in¬
dex finger of the hand you would nor¬
mally use to hold a probe during tests.
Clip the alligator clips on the black and
red twisted-pair hookup wire to the -
and + supply lines of the circuit under
test. Then, using the probe is as simple
as pointing your finger. O

BY WAYNE KASHINSKY

Build a
Miniature
Digital
Stopwatch

Times from 1/100 s to 59 min , 59.99 s
in split or Taylor modes.

THERE have been many sports timer
construction articles, but never one
for a project as small as this. Although
this six-digit LED readout timer can
measure time intervals from one 1/100
of a second to 59 minutes, 59.99 sec¬
onds, it can be held easily in the palm of

DECEMBER 1976

the hand and stored in a shirt or jacket
pocket. Timing can be in either the split-
cumulative mode (display frozen when
start-stop pushbutton is depressed
and total elapsed time with each succes¬
sive switch operation) or the Taylor-
sequential mode (time interval displayed

between successive switch operations).

The single 1C used in this timer has a
built-in crystal-controlled oscillator, a
low-battery indicator (decimal points
come on), and internal digit and seg¬
ment drivers. The output transistors can
handle up to 20 mA per segment and do

PARTS LIST

B t — Three AAA ceils in series
Cl -8-40- pF subminiature trimmer capacitor
(optional, see text)

DIS1 — Common-cathode six-digit calculator
readout stick on 2-ln. board
IC1 — 7205 timer (Intersil)

SI , S2 — Spdt subminiature slide switch
S3. S4 — Spst miniature pushbutton switch,
normally open

XTAL — 3.2768-MHz crystal

Misc. — Plastic case and cover (Pomona 2104
or similar), 24-pin 1C socket (optional),
Molex pins (optional), press- on type or fine
brush and white paint, hook-u^wire.

Note — The following are available from AD¬
AGE, Box 1004, New Brunswick, NJ
08903: kit Kl, consisting of TCI and
XTAL, for $21.95; kit K2, consisting of all
parts, including drilled case, except batter¬
ies, for $39.95. Include $1.50 for shipping.
New Jersey residents, add 5% sales tax.

Fig. L Complete timing circuit is contained in 7205 IC.

not require external current-limiting re¬
sistors. The total average current de¬
mand is less than 40 mA so that three
AAA cells or 3-N rechargeables can be
used as the power source for up to 12
hours. When the battery voltage drops
below 2.6, the indicator comes on. Gen¬
erally, the timer can still be used for
about 15 minutes after this occurs. The
simplicity of the circuit can be seen in
Fig. 1 . A complete description of the cir¬
cuit’s operation cah be found in the Au¬
gust, 1976, issue of Popular Elec¬
tronics, p. 73.

Construction. Although any type of
construction can be used, to make the
sports timer as small as possible, the foil
pattern shown in Fig. 2 should be used.
Note that components are mounted on
both sides of the board as shown in Fig.
3. The IC is mounted on the blank side
of the board, preferably using a socket
58

or Molex pins, or it can be soldered in
place, depending on the cells used.

The LED display is a conventional 2-
inch calculator 6-to-9-digit stick with
flat red lens. In the prototype, an
NSN-66A (National Semiconductor) was
used, but a brighter readout can be ob¬
tained with an NSA-1 1 88. Other types of
readouts can be used if the appropriate
jumpers are made from the display pads
on the board. The NSN-66A can be
mounted on the foil side of the board as
shown in Figs. 2 and 3. If the bottom sur¬
face of the display stick has exposed
bare copper leads, cover it with a layer
of masking tape to avoid shorting to the
pc foil pattern. Mount the display and
switches so that the tops of the switch
bodies are flush with the upper surface
of the display.

All wire connections to the board are
made through the blank side of the
board using slender flexible insulated

wire. The batteries are wired in series
and formed into a small bundle.

For the prototype a small plastic case
was used for the timer. It measured 2%"
W x 1 V4*H x 1 WD, with a fitted cover.
Drill holes for S3 and S4 on one side of
the case with sufficient spacing for the
crystal between them. With the switches
mounted on the case and connected to
the proper points, solder the power
leads to the AAA cells. Then fit the cells
into the bottom of the case and put the
pc board in the case with the display be¬
tween the two switches. The edges of
the pc board (and possibly the display)
may have to be trimmed to make a pro¬
per fit. Insert the pc board until the upper
surface of the display is just slightly be¬
low the rim of the case. The operating
handles of SI and S2 should stick above
the case rim.

Once the board has been properly po¬
sitioned, determine the locations of the
readouts and SI and S2 and cut the
necessary slots in the cover. Install the
cover and identify all the switches with
a white dry-transfer lettering kit. Using
the same careful techniques, apply a
decimal point on the upper surface of
the display just to the left of the two di¬
gits on the right end. Then apply a colon
to the left of the second pair of digits.

If desired, an spst switch can be add¬
ed between IC1 pin 19 and the negative
side of the battery. Operating this switch
will permit the display to show the run¬
ning clock at any time.

(BLANK SIDE) | - XTAL — i

Cl | (BLANK I

A i SIDE) I

Fig. 2. Etching and drilling
and component installation guides .

POPULAR ELECTRONICS

Fig . 3. Top and bottom of board .

Testing. Place Si (on-off) in the on
position and note that the display is .00.
Depressing S3 (start-stop) should
cause the display to start counting in
hundredths of a second. The 1C has
built-in automatic power-on reset and
leading zero blanking so that the other
digits will not be displayed until they are
needed. Depressing S3 again should
cause the display to stop and indicate
some elapsed time.

If only one digit comes on and it is
very bright, the internal oscillator is not
working. Examine the crystal circuit. If
segments are missing, check the two pc
boards for solder bridges or broken
traces. If a segment and digit-driver line
are shorted, that particular segment will
not glow.

Once the timer operates correctly, it
can be checked by listening to WWV or
CHU. Place S2 in the split position and
start the timing on the minute signal.
Check the time against the signal every
few minutes to determine the timer ac¬
curacy. If the displayed time is more
than it should be, mount a small trimmer
capacitor (8 to 40 pF) on the pc board as
indicated in Fig. 2. Adjust the capacitor
and continue the timing tests until the
desired accuracy is obtained.

Using the Timer. The start-stop

pushbutton is used as in a mechanical
stopwatch. The reset button zeros the
counter.

In the split mode, operate the start-
stop button at the beginning of an
event; then once more when the desired
interval (half or full lap, etc.) is finished.
The display will indicate the elapsed
time. However, the counter is still oper¬
ating, so depressing the start-stop
switch again causes the display to indi¬
cate the total elapsed time since the
start of the event. If desired, operate the
reset pushbutton to stop the counter
and return it to zero.

The taylor mode automatically re¬
sets the counter to zero with each oper¬
ation of the start-stop switch, and the
display shows the time interval between
depressions. This is a useful function
when you want to time each lap in a race
without resetting the timer to zero. O

Digital

Fuel

Gauge

BY GREGORY BAXES

Replace your old analog meter with a bright
LED display indicating percentage of fuel remaining.

THE FUEL gauge in most motor vehi¬
cles is a simple electrical meter-type
movement that constantly monitors a
changing current through a sensor locat¬
ed in the fuel tank. It is a simple matter to
convert the monitoring system to a digi¬
tally generated numeric display and
eliminate the uncertainties involved with
reading and interpreting meter-type dis¬
plays. Furthermore, a numeric display is
much easier to read at a glance, which

DECEMBER 1976

adds up to greater driver safety on the
road or highway.

The digital fuel gauge described in
this article can be installed in just about
any motor vehicle to display the quantity
of fuel remaining in the tank in 10’s of
percent. It uses readily available low-
power TTL logic and linear IC’s and
large, easy-to-read seven-segment LED
displays. The entire project can be built
for about $25.

About the Circuit. The block dia¬
gram of the basic gas gauge circuit is
shown in Fig. 1. Note that although the
system is rigged to display three digits
(to represent from empty, or 0, to full, or
1 00%), the units digit is a dummy seven-
segment display that is always powered
to show a 0; it is not driven by the cir¬
cuit’s logic as are the 10‘s and 100’s di¬
gits. Since only 11 increments are actu¬
ally displayed by the system, only 1 Vi di-

DIS l DIS 2 MS 3

Fig. 1. Block diagram showing how gauge works.

gits are required. Hence, DIS1 is either
blanked or displays a 1 .

Integrated circuit IC2 serves as the
clock generator for the system, operat¬
ing at about 1 Hz. It drives a convention¬
al decade-counting system consisting of
counter /C3, latch /C4, decoder/driver
/C5, and display DIS2 . Under normal
conditions, this counter simply cycles,
with the clock pulses, from 0 to 9 and
then generates an “overflow” pulse. In
this system, however, the BCD outputs
from IC3 are also coupled to BCD-to-
decimal decoder IC7. The 0-through-9
outputs from IC7 and R19 through R29
generate a voltage that is proportional to
the count at any instant. This voltage
and a second voltage that is determined
by the amount of fuel left in the gas tank
are summed in voltage comparator IC8.
The output of IC8 is either high or low,
depending on the differential between
the two input voltages.

The values of weighting resistors R19
through R29 are selected to provide
10% changes in the display count. If, for
example, the tank is 50% full, when the
IC3 through IC7 circuit “sees” a 5, ICffs
output changes state to activate the IC6
control circuit. Dual monostable multivi¬
brator IC6 generates a strobe pulse to
cause a 5 to be displayed by D/S2.
Shortly after this, IC6 generates a reset
pulse to allow the circuit to cycle again.
In our example, the display system will
indicate 50%.

The only time the system displays
1 00% is when the gas tank is full. At this
time, IC3 counts through 9 and goes to
0, generating an overflow, or “carry,”
signal. The carry signal passes to the
overflow logic and is used to turn on the
1 in DIS1 when the strobe pulse ap¬
pears.

The reset pulse will return the system
back to 0 so that the cycle can repeat.
Thus, the display is updated every sec¬
ond or so, depending on the rate of the
clock. The display will not flicker, how¬
ever, because the latch in the used 1 x/i
digits will maintain power to the digits
between strobe pulses.

Although, with slightly more logic, the
gas gauge could have been designed to
provide a full 100-step resolution, an 1 1-
step resolution was selected for practi¬
cal reasons. A greater than 10% resolu¬
tion would have resulted in an annoying
fluctuation of the numerals displayed by
DIS3 as the motion of the vehicle
caused the level of the gas in the tank to
rise and fall.

The complete schematic diagram of
the gas gauge is shown in Fig. 2.

Construction. You can use either a
printed circuit board of your own design
or perforated board to assemble the gas
gauge. In either case, it is recom¬
mended that you use sockets for all IC’s
to obviate the possibility of heat damage
to these components during soldering. It

is also suggested that you use two
boards — one for the display and a sec¬
ond for the rest of the circuit. Use color-
coded hookup wire for the interconnec¬
tions between the boards.

There are three external connections
to be made for the gas gauge: +12 volts
to the vehicle’s electrical system, vehicle
ground, and the “hot" side of the fuel
sensor. This is most practically accom¬
plished with the aid of a three-lug screw-
type terminal strip mounted on the rear
of the case in which the circuit is
housed. Additionally, if you prefer, volt¬
age regulator IC9 can also be mounted
on the case, provided the case is metal,
for heat-sinking purposes.

Note in Fig. 2 that the values of resis¬
tors R19 through R29 are not specified.
These resistor values must be deter¬
mined for the specific fuel sensor with
which the gas gauge is used. To deter¬
mine the values of these resistors you
must first locate the “hot” lead of the fuel
sensor going to the meter on the vehi¬
cle’s dashboard. Break this lead so that
you can measure the sensor’s re¬
sistance between the lead and ground.

There are two ways to obtain a rela¬
tively accurate list of fuel-sensor mea¬
surements. First, you can drive your car
into a gas station with your car’s meter-
type fuel gauge still connected and reg¬
istering empty. (Do not completely emp¬
ty your tank of gas. If you assume an
empty tank when the gauge reads emp¬
ty, you will have a margin of safety when
your tank runs low.) Have the attendant
fill your tank to full and keep a record of
the amount of fuel required to fill the
tank. Divide the number by 10. You now
know gallons at each 10% point. Then
the next time you go for a refill, discon¬
nect the “hot” sensor lead from the me¬
ter and have the attendant fill your tank
in the previously noted 10% increments
while measuring and logging the sen¬
sor’s resistance at each 10% point.

The second way is to estimate the
1 0% marks on your car’s meter-type fuel
gauge, marking these points on the me¬
ter’s faceplate with a grease pencil. Fill
your tank to full, install a switch in the
sensor’s “hot” lead, and (with the switch
closed) drive around until the meter’s
pointer registers 90%. Pull over, open
the switch, and measure the sensor’s re¬
sistance. Repeat this procedure until the
meter registers empty, keeping a log of
your measurements. Again, do not drive
your car until the tank is completely
empty. Remove the switch from the sen¬
sor’s hot lead.

The resistance measured for an emp¬
ty tank is the value of R19 at pin 1 of IC7,
POPULAR ELECTRONICS

1 1

SEGMENT*

, 7SJ1

b,c

VEHICLE

FUEL

SENSOR

CHASSIS GNDO-

8-^ 3| C6«**rN -nr^.C9

>*jF| J.lpF JjiFj 470jiF

Fig . 2. Complete schematic
of the digital fuel gauge .

PARTS LIST

Cl— iO-jiF, 10-volt electrolytic capacitor

C2 through C7, CU>— 0. 1-p.F, 10-volt capa¬
citor

C8, C9 — 470-jtF, 15-volt electrolytic capa¬
citor

DU D2—1N4454 diode

DISU DIS2, DIS3— MAN-52 (Monsanto) or
any common-anode seven-segment LED
display

IC I— 74L74 dual D flip-flop

IC2 — 555 timer

IC3 — 74L90 decade counter
IC4 — 74L75 latch

ICS — 74L47 seven-segment decoder/dri ver
IC6 — 556 dual timer

IC7 — 74L45 BCD-to-decimal decoder/driver

IC8 — LM3 1 1 voltage comparator

IC9 — LM309K 5-volt regulator

Q1 , Q2 — 2N4946 transistor

The following resistors ape Va watt, 10%:

R U R2 » R3 , R 1 6, R1 8—2000 ohms
R4 — 75 ohms
R5 — 1 megohm

R6 — 390 ohms
R7,R17— 10,000 ohms
R8 through R15 — 150 ohms
R30,R3 1—220 ohms

R19 through R29 — Trimmer potentiometer
(see text)

R32 — 25 ohm, 10%, 1^-watt resistor
Misc.-^ferforated dr pc board; sockets for
IC\s (optional); chassis box; whjffe dry-
transfer lettering kit; red plastic disjftay win¬
dow; hookup wire; solder; machine hard¬
ware; etc.

while the resistance measured for a full
tank is the value of R29 at pin 1 1 of IC7.
All other resistances are the values of
R18 through R28 and fit into the circuit in
consecutive order between pin 2 and pin
10 of IC7. (Note that pin 8 of IC7 goes to
DECEMBER 1976

ground; skip this pin when installing the
resistors.) You can use miniature pc-
type trimmer potentiometers for R19
through R29.

If your tank’s fuel sensor resistance
increases as the fuel decreases, con¬

nect the inputs of IC8 to pins A and A' as
shown with a jumper. If the tank sensor’s
resistance decreases as the fuel level
decreases, connect the inputs of IC8 to
B and B'

Once the digital fuel gauge project is

assembled, mount a red plastic window
in front of the displays. Then, using a
white dry-transfer lettering kit, label the
legends fuel above and percent be¬
low the displays. (If you prefer, you can
paint a white % sign on the window.)

Once the project has been assem¬
bled, it can be installed in your vehicle
on top of the dashboard or in any loca¬
tion where it provides an unobstructed
view of the displays. Make the three
connections to the vehicle’s electrical

system: (1) +1 2-volt power input line to
any point in the system that is powered
when the ignition is on and off when the
ignition is off; (2) ground to the vehicle’s
chassis ground; (3) sensor to the “hot”
side of tf^fuel sensor. o

An A/D

BYW.J.PRUDHOMME

Temperature

Converter

Use your frequency counter
to measure temperature
to 0. 1 °C resolution.

THIS project is a low-cost analog-to-
digital converter which allows you to
make accurate temperature measure¬
ments with a frequency counter. Its
range is 0° to 100°C, with a resolution of
0.1 °C and an accuracy of 0.5°C.

The circuit uses an inexpensive sili¬
con signal diode as a temperature sen¬
sor, a dual operational amplifier 1C, a
unijunction transistor, and a handful of
resistors and capacitors. Parts cost is
less than $10. No warm-up period is re¬
quired, and the project is easily calibrat¬
ed. Several sensors can be switched
into the circuit to provide temperature
readings at various locations.

About the Circuit. The converter’s
schematic diagram is shown in Fig. 1.
When power is applied to the circuit,
zener diode D1 and resistor R6 set up a
reference 1-mA current through temper¬
ature sensor D2, a 1N914 silicon signal
diode. When D2 conducts, it exhibits a
forward voltage drop of approximately
0.7 volt at room temperature (25° C). But
this voltage drop is temperature depend¬
ent. For each 1° C increase in ambient
temperature, the forward voltage drop
decreases 2.2 millivolts. Conversely, for
62

each 1°C decrease, the voltage drop in¬
creases 2.2 millivolts. This voltage sig¬
nal is applied to the noninverting input of
IC1A , an op amp integrator.

When the voltage across integrating
capacitor Cl reaches a certain value,
unijunction transistor Q1 turns on, dis¬
charging Cl. Potentiometers R2 and R5
set the minimum and maximum charge/
discharge rates, respectively. Each time
Cl is discharged, an output pulse is
generated. This pulse is coupled to the
noninverting input of IC1B , an op amp
buffer whose gain has been selected to
produce a pseudo-square-wave output.
The output signal, appearing at J2 , is
then coupled to the frequency counter
input by a short jumper of coaxial cable.

The conversion ratio of the A/D con¬
verter is 1 0 Hz per degree C when prop¬
erly calibrated. That is, when the mea¬
sured temperature is 25.4° C, the coun¬
ter will indicate a frequency of 254 Hz.

A bipolar (±9-vo!t) power supply is re¬
quired. A line-powered dc source can be
used, but two 9-voit transistor batteries
connected in series are also suitable.

Construction. Circuit layout is not
critical, so printed circuit or perforated

board can be used. Etching and drilling
and component layout guides for a suit¬
able pc board are shown in Fig. 2. Trim¬
mer potentiometers R2 and R5 can be
fashioned from vertical mounting types.
Simply bend the three lugs on each so
the controls can be mounted flat against
the circuit board. Be sure to observe
proper polarity and basing on the 1C,
and other semiconductors. The use of
an 1C socket or Molex Soldercons is rec¬
ommended.

Temperature sensor D2 should be
connected to a length of shielded cable
terminated with a phono plug. Be sure to
connect the diode so that its cathode is
I grounded. Otherwise, false readings will
be obtained. Also, it is recommended
that you dip the diode in clear epoxy ce¬
ment after it has been soldered. Allow
the epoxy to cure for 24 hours before us¬
ing the sensor. This will give a protective
coating around the diode.

Connection to the frequency counter
should also be made with a jumper of
shielded cable terminated with proper
plugs. You may want to use the same
jack for J1 as is on the counter, such as
a BNC jack. Alternatively, a phono jack
can be used.

POPULAR ELECTRONICS

PARTS LIST

B 1 , B2 — 9-volt transistor batteries

C l — 0.0047-piF silver mica or polystyrene ca¬
pacitor

C2 — 620-pF silver mica or polystyrene capaci¬
tor

D1 — 6.2-volt, I -watt zener diode (1N821 or
equivalent)

D2 — 1N914 silicon signal diode

IC1 — 747 A dual operational amplifier

Jl, J2 — phono jacks
PL1 — phono plug

Q1 — 2N2646 or Radio Shack 276-111 uni¬
junction transistor

The following resistors are 10%, V*- watt un¬
less otherwise specified:

R1 — 5600 ohms

R3 470 ohms

R4 — 1000 ohms

R6 — 6200 ohms, 5% tolerance

R7 — 1.2 megohms

R8 — 100 ohms

R9 — 10, 000 ohms

R2 — 1000-ohm printed circuit trimmer poten¬
tiometer

R5 — 10,000-ohm printed circuit trimmer po¬
tentiometer

SI — Dpdt toggle switch

Misc.— ^Battery clips, suitable enclosure,
hookup wire, shielded cable, IC socket or
Molex Soldercons, machine hardware, sol¬
der, etc.

Fig. 1 . In converter circuit , signal diode D2 acts as a linear temperature sensor .

► R -*

Fig. 2. Actual-size etching
and drilling guide at right
Parts placement guide above.

Calibration. Once the circuit has been
built and is operating, it should be cali¬
brated at both extremes of its range.
With the converter connected to the fre¬
quency counter, insert the temperature
sensor into a bath of boiling water. Ad¬
just R5 so that the frequency counter
reads 1000 Hz (100°C). Then insert the
sensor in a container of crushed ice and
adjust R2 for a 0-Hz (0°C) reading. Be¬
cause there is a degree of interaction
between the two controls, the procedure
must be repeated several times until
proper readings are obtained at both
temperature extremes.

DECEMBER 1976

Operation. Once the project has been
calibrated, it will exhibit excellent lineari¬
ty over its entire temperature range. A
rotary switch can be added if remote
sensing at several locations is desired.
The shortest possible length of shielded
cable should be used with each diode. A
voltage drop in the wire of even a few
millivolts (that has not been compensat¬
ed for in calibrating the project) will
affect the converter’s accuracy. If the di¬
ode sensor is damaged at temperature
extremes, simply replace it with another.
The cost of signal diodes is low enough
for you to keep many spares on hand. O

'* That's the third paragraph you 've
started with ‘according to our computer. ' "

BY RALPH TENNV

/■

The

Logic Gremlin

Where those “glitches” come from and what to do about them

IOGIC circuits usually behave very
■ logically. For example, trigger a flip-
flop and its outputs change state; or
drive an inverter and the signal flips
over. What could be simpler?

Unfortunately, “glitches” (undesired
signals) sometimes get into a circuit and
cause it to misbehave. When you look
into the problem, you find that all the di¬
gital logic IC’s are good; the clock is fine
and healthy; the power supply is clean
and well-regulated; and the wired inter¬
connections are all OK. But the circuit
still produces erratic results!

If you are blessed with a high-quality
oscilloscope, it is possible to spot mys¬
terious glitches wandering around the
circuit, appearing like that shown in Fig.

Fig . 1. Retouched photo of glitch.

1 . If this signal is applied to a logic cir¬
cuit, the circuit will trigger on the glitch
as well as on the leading edge of the real
signal. This produces an erratic result. In
this article, we will discuss the sources
of such glitches and how to eliminate
them, if possible.

Basic Element. Let’s begin by con¬
sidering the simplest logic element— the
basic inverter. Although it seems that
the input and output of an inverter occur
in step with each other, this is not the

a — D>° — a

I PROPAGATION

- -i k - DELAY

Fig. 2. Inverter output delay.

case. These devices require a finite
amount of time to respond to a signal in¬
put. This “propagation delay" is shown
in Fig. 2. Specification sheets for the log¬
ic device give the amount of delay to be
expected. Interestingly, propagation de¬
lay is not related to waveform rise and
fall time and is different for positive¬

going and negative-going waveforms.
To further complicate matters, many
TTL specifications sheets list both mini¬
mum and maximum delay times, with
both specified for a standard resistive
and capacitive load. Any extra capaci¬
tance in the load will simply produce
more delay.

For example, if two TTL devices such
as the 7400 quad 2-input NAND gate
and the 7404 hex inverter are combined
in a circuit that depends on propagation

Fig. 3. Making use of the glitch.

delay (sometimes we can make the
glitch work for us), we can observe the
effect of typical and maximum delay
times. The circuit, a propagation delay
one-shot, is shown in Fig. 3 with its as-

POPULAR ELECTRONICS

Fig. 4. Circuits in (A) should produce waveforms at (B). But (C) shows a glitch.

sociated waveforms. The positive-going
edge (A) causes the output to fall one
delay time later (B). At about the same
time the output at (C) falls. One more
delay later, output (D) rises. Finally three
delays after input (A), output (E) drives
output (B) high. The solid lines show an
ideal situation while the dashed lines
show how propagation delay affects the
width of the output pulse. Note that the
output pulse width depends on the com¬
bined propagation delays of the devices
used.

The question then is: which delay fig¬
ures should be used? The answer is: the
worst-case figures. That is simple
enough, but which is the worst case?
The answer to that depends on the ap¬
plication. The designer must decide
what effect a slow or fast (responding)
device will have on each part of the cir¬
cuit under consideration.

Predicting Propagation Delays.

Here is one method that can be used to
predict whether propagation delays will
cause an unwanted glitch. Two divide-
by-two circuits are shown in Fig. 4A. In
the circuit on the left, a NAND gate is op¬
erated by a flip-flop. In the other circuit,
the gate is a NOR. Theoretically the out¬
put waveforms of the two circuits would
be similar and would look like those in
Fig. 4B. However, Fig. 4C shows the ac¬
tual output as viewed on a scope, except
that AND and OR gates were used and
the top waveform was inverted from that
shown in the NAND portion of Fig. 4B.
Now, where did that glitch come from?

To answer this question, we will re¬
draw Fig. 4B using a time scale of 50 na¬
noseconds per division and take propa¬
gation delay into account. Fig. 5A is the
result. Note that the glitch is produced
by the overlap between the clock and
the Q output caused by the propagation
delay in the flip-flop. In the case illustrat¬
ed, it was assumed that the flip-flop had

maximum delay and the gates were typi¬
cal devices — which makes the largest
glitch. Fig. 5A does not look exactly like
Fig. 4B because the latter was drawn as
if the waveform transitions were instan¬
taneous, which they are not. The effects
provided by rise and fall times are
shown in Fig. 5B.

So far we have considered only sim¬
ple circuits. Clearly, by choosing the OR
gate in Fig. 4A, we avoid the glitches.
Now, suppose the design requires a
source of timing signals derived from a
counter. In the circuit in Fig. 6A, a 74197
counter drives a 741 54 decoder to pro¬
duce the waveforms shown in Fig. 6B.
The circuit produces 16 sequential tim¬
ing pulse outputs, but only five are
shown in Fig. 6B. So far, so good. Unfor¬
tunately, if you look at the output on a
scope, the waveform in Fig. 7A is the re¬
sult. This is not a pretty picture! What
went wrong?

The 74197 is a ripple counter. This
means that the input clock toggles the
flirst flip-flop, which in turn toggles the
second flip-flop, etc. Eventually, the sig¬
nal propagates to the output. The spec
sheet for this device indicates a max¬

imum of 60 ns delay, with a minimum of
1 0 ns for each stage. Next, in the 741 54,
the inputs are buffered by an inverter
and then inverted again as necessary
for the final decoding. The interlocking
arrangement of inverters and gates pro¬
duces differential delays and thus per¬
mits the occurance of glitches — even if
the decoder inputs are synchronized. In
this case, the solution is to feed a narrow
clock pulse to the enable inputs of the
741 54, then invert the clock to drive the
74197 counter. This “de-glitcher” is
shown by the dotted lines in Fig. 6A. If
the clock pulse is wider than the counter
delay, the output signals become as
clean as those shown in Fig. 7B.

Solutions. We can now summarize
the points covered and learn a little more
about de-glitching:

1 . Glitches are caused by unbalanced
propagation delays in the signal path. In
theory, the glitch of Fig. 5 could be elimi¬
nated by adding a delay in the circuit as
shown in Fig. 8. This would require that
both inverters and flip-flop have “typical”
delay specifications.

2. In general, decoding with OR/NOR

CLK l

' \t -1

•

NANO l

~~ u

J ■

(A)

clk_/

0_J

i —

— L_/ 1

i _ r~

l_j \ _ r

\ _ r

NAND

LJ — 1

J klj

f— [

- (B)

Fig. 5. Expansion of Fig. 4B shows propagation delay.

DECEMBER 1976

Fig . 6. Dotted circuit in (A) is
added to remove glitches.

Fig. 7. Enable gating removes
glitches in (A) to give (B).

gates, as in Fig. 4A, eliminates glitches.

3. Some logic devices incorporate en¬
able inputs, which, if properly used, can
eliminate glitches.

4. Some functions can be performed
differently, such as by using synchro¬
nous counters like the 74193/74163 in¬
stead of ripple counters like the
7490/74197.

5. Though some logic families such as
CMOS have slow rise times and slow
operation (which should eliminate
glitches), remember that any logic family
will respond to glitches produced by that
logic family.

6. In many cases, glitches can be
eliminated by flip-flop sampling. If you
have a glitched output that comes from a
“black box” that can’t be de-glitched by
simple methods, use the circuit shown in
Fig. 9A. The black-box output is fed to a
D flip-flop that is clocked by the system
clock. Propagation delay of the black
box causes the glitches to fall between
the clock pulses, but the real signal is
available at the correct times. Note in
the Fig. 9B that the flip-flop output is free
of glitches but has been delayed one

clock period plus the propagation delay
of the flip-flop. If there are critical timing
path considerations in the circuit, then it
may be necessary to make some delay
adjustment in one of the other “down¬
stream” circuits.

7. An RC delay can be used to combat
narrow glitches using the technique
shown in Fig. 10A. Timing waveforms
are shown in Fig. 10C. By proper selec¬
tion of the RC time constant, the delay
across the RC network is longer than the
glitch time and the glitch disappears. For
extra long glitches, it may even be nec¬
essary to use two RC networks separat¬
ed by a logic gate as shown in Fig. 10B.

The RC de-glitching method is just
barely acceptable for TTL logic for two
reasons. The first is that since the TTL
inputs require 1 .6 mA drive, the resistor
is limited to about 180 ohms. This re¬
quires the use of fairly large-valued ca¬
pacitors — on the orcj^r of 1000 pF. Even
so, the 180-ohm resistor reduces the
noise immunity of the input it feeds. The
second reason is that the large-valued
capacitors require large drive currents
from the TTL. Since CMOS logic has

BLACK

BOX

A . * F

black I

BOX r

—

10. RC delay
can be used to
remove narrow
glitches .

Fig. 8. Modification of Fig. 4.

^JL^LJLJLJLJLrLJL^

» I _ I - l_l - L

<B)

Fig. 9. Flip-flop removes glitches.

very high input impedance, the RC delay
is very effective as a CMOS de-glitching
method.

8. One particular type of TTL logic that
will tolerate large values of RC time con¬
stants for de-gtitching is the TTL Schmitt
trigger. Figure 11 shows circuits and
waveforms using the 7414 (hex Schmitt)
and 74132 (quad 2-input Schmitt) for
this purpose. It is still necessary to limit v
the resistor value to about 330 ohms us¬
ing these devices. The CD4093 is a
CMOS quad 2-input Schmitt trigger de¬
vice that is very effective for de-glitching
and delay using resistor values up to
about 100,000 ohms.

9. A CMOS buffer (CD4010, CD4050)

can be used for de-glitching, delay, and
even switch debouncing with the circuit
shown in Fig. 12. Feedback resistor R2
determines the hysteresis of the circuit
(the Schmitt trigger action) while the
time constant of R1/C sets the amount
of delay. O

x x

(A)

H p — DELAY

(B)

Fig. 11. Schmitt trigger solution.

Fig. 12. CMOS de-glitcher.

POPULAR ELECTRONICS

NEED HARDCOPY?

:+: SHTPC PR-48 ALPHANUMERIC PRINTER *

If you are one of the many computer
users who wants hardcopy printouts,
but can't afford any of the available
machines, your troubles are over. Our
PR-40 is a universal printer that gives
you clear easy to read hardcopy like
the sample on the right with almost
any computer. Our printer operates
from any eight bit parallel I/O port.
The printer has it's own character
generator and memory buffer. This
means that the computers only job is
to feed data when the printer is ready.
No special program is needed in the
computer to convert the data to a
form that the printer can use as each
character is printed. The PR-40 is easy
to use, easy to interface and easy to
afford.

40 CHARACTERS / LINE

5X7 DOT MATRIX IMPACT. PRINT

USES STANDARD 2 7/8" CALCULATOR PAPER

75 LINE / MINUTE PRINT RATE

AUTOMATIC RIBBON REVERSE

64 CHARACTER ASCII CHARACTER SET

40 CHARACTER LINE MEMORY

TTL.. SHTPC 6860, HITS COMPATIBLE

PR-40 LINE PRINTER KIT . $250.00 PPd

HOW ABOUT PICTURES?

Games are more fun with pictures. Now you
can add graphics displays to your game pro¬
grams and on any type computer. Our GT-
6144 operates from any eight bit parallel I/O
port. It has it's own self contained memory,
so memory space for the display is not robbed
from your computer. The 9yz x 13 circuit
board contains all you need to produce a
graphic display like the one of the starship
"Enterprise" shown on the left. Kit is less
power supply, or chassis.

GT-6144 GRAPHICS TERMINAL KIT. .$ 98.50 PPd

1 know a bargain when 1 see it. Send the following:

□ 6800 Computer $395.00 □ PR-40 Printer $250.00

□ GT-6144 Graphics Terminal $* 98.50 □ Just data (free)

NAME

,-J

ADDRESS

_ COMPUTER

Sijifii 6BOO SYSTEM

Southwest Technical Products Corp.
Box 32040, San Antonio, Texas 78284

DECEMBER 1976

CIRCLE NO. 61 ON FREE INFORMATION CARD

H you can see a difference,
imagine what you’ll hear.

With

Sound Guard

Unprotected

Distortion

components

Sound

Guard..

Record

Preservation

Record

Preservative

2 FLOz.
59.14 ml

Guard preservative played while reducing distortion and identical test record after

100 times display the same surface noise.” It’s effective and 100 plays ^ “ Guard-

full amplitude at all frequen- safe for all discs, from precious velvet buffing pad, is avail-

cies and the same absence of old 78’s to the newest LFs. able in audio and record

surface noise and harmonic Sound Guard preservative, outlets.

Sound Guard keeps your good sounds sounding good.

CIRCLE NO. 60 ON FREE INFORMATION CARD

BY DON LANCASTER

Active

Filters

Using op amps makes filter design easy and low-cost.

Frequency-selective filters

(high-pass, low-pass, or band¬
pass) can be either passive or active.
The former is traditionally an inductor-
capacitor circuit which, particularly at
audio frequencies, can be cumbersome
and expensive and have a response
shape that is not as selective as desired.
Active filters use conventional resistors
and capacitors and operational amplifi¬
ers. They are low in cost, easy to tune,
not sensitive to field and hum, small and
light, and are not influenced by varying
load and source impedances. In addi¬
tion, active filters can be easily cascad¬
ed, so that a complex filter response can
be broken down into simple factored
blocks that do not interact.

Where are active filters used? Elec¬
tronic music is one obviously impor¬
tant area. Here, active filters serve as
modifiers of conventional instruments,
to generate new sounds by way of
formant synthesis and vcf (voltage
controlled filter) techniques, and to
DECEMBER 1976

generate the transient responses in¬
volved with bell and other percussion
voices.

Biofeedback circuits that monitor
brainwaves use ultra-low-frequency ac¬
tive filters to separate the alpha, beta,
delta, and theta response waves. Ac¬
tive filters are also used in graphic
equalizers to permit modifying the au¬
dio channel response to suit individual
tastes or room acoustics. Micropro¬
cessor and computer-related uses of
active filters include cassette tape sine-
wave generators for data recording
and transmission and reception of mo¬
dem (modulator-demodulator) systems
that send data over the phone lines.

Laboratory applications are wide¬
spread, ranging from ultra-low-frequen¬
cy seismic and geophysical signal
processing, to speech and hearing stud¬
ies, and Doppler tracking of moving ra¬
dar targets. Elaborate, general-purpose
active filters are also available for many
different lab situations where certain fre¬

quencies must be emphasized and oth¬
ers rejected or minimized. These same
circuits can be converted into high-qual¬
ity signal sources with external feed¬
back.

The biggest users of active filters
are probably engineers at the phone
company. They developed most of the
math concepts behind active filters
and have an incredible variety of uses
for them, ranging from multiplexing of
phone conversations onto a common
carrier to equalization of telephone lines.

Psychedelic lighting systems use
active filters to pick up an audio sig¬
nal, break it down into various fre¬
quency channels, and modulate colored
lights or lasers on a multicolor dynamic
display.

Actually, today you can use active
filters for just about any frequency
selective task you can dream up, rang¬
ing in frequency from a few hun¬
dredths of a hertz to several hundred
kHz or more. The most common types

of filter you’d be interested in are
low-pass, band-pass, high-pass, univer¬
sal, notch, and voltage-controlled fil¬
ters. Now, let’s take a detailed look at
how you can build your own active fil¬
ters.

Low-Pass. Active filters are normally
broken down into building blocks that
are simple and easy to tune. For fan¬
cier responses, you combine as many
simple blocks as you need to get the
overall desired result. One popular
building block is called a second-order
section. A second-order low-pass is
pretty much flat in response up to a
cutoff frequency. Above that, the re¬
sponse drops by one fourth each time
you double the frequency. We say it
has a cutoff slope of -12 dB per oc¬
tave. A “mirror image” high-pass se¬
cond-order section will have a comple¬
mentary slope of +12 dB per octave,
leveling off near the cutoff frequency
and staying uniform for higher frequen¬
cies. Each of the second-order sec¬
tions uses one or more operational
amplifiers. For most lower frequency
audio work, the 741 op amp is ideal.

Improved 741 ’s, particularly the duals
and quads (4558 and 4136 are typical)
are now available at low cost. Where
you really need high-"Q” values or
large signal swings at high frequen¬
cies, you can turn to a super 741 such
as the LM318, with fifteen times the
bandwidth and 1 50 times the slew rate
of a stock 741. Or, if you’re into very-
low-frequency work, it pays to raise the
impedance levels of your circuit as
high as possible to get by with smaller
valued capacitors. The FET or CMOS
op amps are ideal for this, with the
3140 being a top choice for many low-
cost applications.

A pair of second-order low-pass ac¬
tive filters, having a 1-kHz frequency are
shown in Fig. 1. Each circuit is flat to
near 1-kHz and then drops at -12 dB/
octave well above 1-kHz. As the fre¬
quency increases, the response contin¬
ues to die out.

The first circuit (Fig. 1A) is called the
unity gain Sallen-Key circuit otherwise
known as a VCVS or voltage con¬
trolled voltage-source filter. Since the
op amp is used as a source follower
(a noninverting amplifier with a gain of

HAVE
0C PATH
TO

GROUND

Fig. 1. Unity gain (A) and equal
component (B) Sallen-Key low pass
filters . See table for values of d.

one, a high input impedance, and a low
output impedance), an ordinary transis¬
tor emitter follower can be used just as
well.

How does the circuit work? It looks at
the overall mathematical transfer func-

RESISTOR AND DAMPING VALUES FOR VARIOUS LOWPASS AND HIGHPASS RESPONSES

First Section

Second Section

Third Section j

Resistor

R (kilohms)

Damping

Resistor

R (kilohms)

Damping

Resistor

R (kilohms)

Damping

Best Delay Low-pass

12 dB/octave

7.87

1.731

—

24 dB/octave

6.98

1.916

6.19

1.241

—

36 dB/octave

6.19

1.959

5.90

1.636

5.23

0.977

Flattest Low-pass

12 dB/octave

1.414

—

24 dB/octave

1.848

10.0

0.765

—

-36 dB/octave

1.932

10.0

1.414

10.0

0.518

1 dB Peak Low-pass

12 dB/octave

11.5

1.045

—

-24 dB/octave

19.1

1.275

10.5

0.281

—

36 dB/octave

28.8

1.314

13.7

0.455

10.2

0.125

Well-Damped High-pass

+ 12 dB/octave

12.7

1.731

24 dB 'octave

14.3

1.916

16.2

1.241

—

+ 36 dB/octave

16.2

1.959

16.9

1.636

19.1

0.977

Flattest High-pass

+ 12 dB/octave

10.0

1.414

—

+ 24 dB/octave

10.0

1.848

10.0

0.765

—

+ 36 dB/octave

10.0

1.932

10.0

1.414

10.0

0.518

1 dB Peak High-pass

+ 12 dB/octave

8.66

1.045

—

+ 24 dB/octave

5.23

1.275

9.53

0.281

—

+ 36 dB/octave

3.48

1.314

7.32

0.455

9.76

0.125

POPULAR ELECTRONICS

OUTPUT

(B)

Fig . 2. Multiple-feedback bandpass
filter (A) is improved at (B)
to have higher input impedance.

tion for an inductor-capacitor-load circuit
and synthesizes a similar result. So,
while it does not actually replace the in¬
ductor, it’s a simple matter with some
fancy math to show that the circuit does
everything that can be done with a pas¬
sive inductor/capacitor filter and then
some.

If the op amp weren’t there, and if
the first capacitor went to ground, we’d
have an old-fashioned two-stage RC
filter. This circuit has unity gain at very
low frequencies (if not loaded), and a
falloff at -12 dB/octave at very high
frequencies. The problem is in-
between where we’d like to have a
sharp passband. Here the RC filter’s
response is very droopy and ill-defined.

Now, when the “ground” end of the
first capacitor is connected to the out¬
put of the op amp, just enough energy
is fed back from the power supply to
simulate the energy storage in an in¬
ductor, and thus bolster the response
as much as we want at the cutoff fre¬
quency. Very nicely, this feedback is
localized only near the cutoff frequen¬
cy. Why? Because the capacitor has
too high a reactance to feed anything
back at very low frequencies; and at
very high frequencies, the output signal
is too small to be worth feeding back.
So, it’s only near the cutoff frequency
that the feedback has any appreciable
effect.

Just how much energy do we want
to feed back? This depends entirely on
how much bolstering of the response

we need near the cutoff frequency, and
thus determines the cutoff response
shape. The amount of feedback is
called “d”, short for damping. The larg¬
er the first capacitor is with respect to
the second the lower the damping, and
the more peaked the response. Values
of d range from two down to zero. A
damping of 2.00 is what we get with
two cascaded but isolated RC sec¬
tions. A d value of 1.73 will give the
best possible transient and pulse re¬
sponse while a d of 1 .41 gives the flat¬
test possible amplitude and also a cut¬
off frequency that’s exactly -3 dB
down (0.707 voltage) from the funda¬
mental. If we lower d further, we get a
hump or peaking near the cutoff fre¬
quency. For instance, d values of
1 .045, 0.895, and 0.767 correspond to
humps of one, two, and three decibels
respectively. If d ever hits zero, we get
infinite peaking, otherwise known as an
output with no input, or an oscillator.

To build the Fig. 1A circuit, we must
decide what the damping is going to
be, and then calculate the two
capacitor values. For a flattest am¬
plitude filter (also called a Butterworth),
d will equal 1.41, and the left capacitor
will be 0.02 |xF and the right capacitor
will be 0.01 |xF, rounded off to stock val¬
ues.

How do we change frequency? By
changing either the capacitors or the re¬
sistors marked “R” or both. The only
thing NOT allowed is to change the
ratio of the two resistors (from
1:1) or the ratio of the two capacitors
(from 4/d2) The product of the resistors
and capacitors sets the frequency. The
ratio of the capacitors sets the damping
figure.

If the capacitor values are doubled,
the cutoff frequency drops to 500 Hz. If
the resistance values are doubled, the
cutoff frequency also drops to 500 Hz.
Do both and the frequency drops to 250
Hz and so on. The capacitors can be
switched in steps and a dual potentiom¬
eter used to change resistance for a
10:1 frequency change.

By the way, note that the frequency
varies inversely with the potentiometer
settings. This will give you a dial that’s
very cramped at one end and nonlin¬
ear. Two ways to beat this problem are
to use pots with reverse log tapers or
to use pots with standard audio log
tapers but put the dial on the pot shaft
and the pointer on the panel, instead
of vice versa. Selector switches and
stepped resistor values provide anoth¬
er route to frequency selection and

usually offer more precise control than
ganged pots. Frequency steps can be
in a linear or log arrangement.

Polystyrene capacitors are excel¬
lent for active filter use, but you have
to keep them away from solvents and
be careful not to nick them with a sol¬
dering iron. More expensive mica and
Mylar capacitors can also be used. Un¬
der no circumstances should a disc or
an electrolytic capacitor be used for fil¬
ters.

There are one or two details that can
cause trouble if you don’t watch for
them. With this circuit or any other low-
pass filter, you have to bias the op
amp’s inputs in some way. This is usu¬
ally done through the source, so there
has to be a low-resistance dc return
path through the source to ground. The
source impedance, dc and otherwise,
should be well below 10,000-ohms if
it’s not going to change the response.
A second detail is to note that this is a
true lowpass filter, so it also passes
dc. Any bias, dc level, or offset voltage
at the input goes on to the output, and
if too large, can saturate the amplifier
or limit the dynamic range. This effect
can be eliminated by putting a blocking
capacitor on the input, but you still
have to bias your op amp. The 20,000-
ohm resistor connected to the negative
input isn’t critical, and usually it is
picked for minimum op amp offset.

While the Fig 1 A circuit is simple and
easy to build, we can do better. The ca¬
pacitor values are hard to calculate and
tend to spread widely for low d values,
thus damping is hard to adjust. There’s
also no easy way to switch from high-

Fig . S. High-pass filters: unity
gain (A) and equal component (B).

DECEMBER 1976

pass to low-pass just by rearranging
components.

If you go through the Sallen-Key
math in detail (a very ugly process), it
turns out that there is one magic value
of op amp gain that solves all these
problems. This is the ultra-simple and
practically unknown equal compon¬
ent value Sallen-Key filter shown in Fig.
IB. The magic gain value is 3-d,
which means that you trim the damping
by trimming the gain. The R resistors
and the capacitors are identical values
and are changed in pairs to change fre¬
quency. As an added feature, it can be
changed to a high-pass characteristic
with identical response simply by inter¬
changing the resistors and capacitors.

One new detail to watch is that the
feedback resistor must be held lower

than the 78,000-ohm value that corre¬
sponds to ad = 0 oscillator. Fortunately,
the d values shown here are normally
well away from this danger zone, and
the gain is easily set by the ratio of two
resistors.

Band-pass. Sallen-Key techniques
don’t really make good band-pass filters,
so we go to the multiple feedback filters
shown in Fig. 2. Usually, we are involved
with such low d values in a bandpass fil¬
ter that we use its inverse or Q instead.
The Q is simply the ratio of the band¬
width to the center frequency. The circuit
of Fig. 2A has a gain of -2Q2 at reso¬
nance (the minus means a 180-degree
phase shift), and a resonance frequency
of 1 kHz.

The circuit is tuned by changing

lower Q values and lower resonance fre¬
quencies. You also tend to get a wide re¬
sistor spread with high Q values so this
circuit is best used for Q values of 20 or
less. At resonance, the gain is very high,
so be sure to limit the size of the input
signals so the op amp doesn’t clip or sat¬
urate.

The extra resistor added to Fig. 2B
raises the input impedance and drops
the gain. However, it still has a re¬
spectable gain of -Q2/5 and ten times
the input impedance of the earlier filter
circuit.

High-pass. The Sallen-Key circuits
can be used for high-pass by making
them mirror images of the low-pass.
These are shown in Fig. 3. Note that the
unity gain version (3A) now has resistor
ratios set by the damping and 1 :1 capa¬
citor ratios, so there is no way to switch
the same parts around for identical low-
pass and high-pass responses. The
equal component value circuit of Fig. 3B
doesn’t have this problem and we get
from high-pass to low-pass with 4pdt
switching. Since there is an internal dc
bias path, we no longer have to worry
about providing a dc return through the
source.

High-pass filters are inherently nois-
er than low-pass ones because they
emphasize transients, and pass har¬
monics of supposedly rejected wave
forms. Certain circuits tend to reduce
the stability margins of the internal op
amp compensation. So, rarely will you
get a really “clean” high-pass output
from a filter, active or passive. Note

FOR MORE INFORMATION

Here are some good sources of in¬
formation on active filters:

The Active Filter Cookbook,

I #21168, Howard W. Sams, In¬
dianapolis, IN 46206, (1975).

“A Practical Method of Designing
RC Active Filters,” IRE Transactions ,
CT-2, March 1955.

“State Variable Synthesis for Insen¬
sitive Integrated Circuit Transfer
Functions,” IEEE Journal, SC-2, Sep¬
tember 1967.

The first of these has the most de¬
tail on circuits, background math, and
tuning techniques (for these and other
circuits), along with many response
curves, rip-off circuits, and detailed
band-pass design information. The
second and third references are
theoretical “horses mouth” source
documents covering the theory be¬
hind Sallen-Key and State-Variable fil¬
ters.

the values of the resistors or the
capacitors, but, once again, both resis¬
tors and both capacitors are kept at fixed
ratios.

The op amp gain should be at least
20Q2 at the operating frequency, so
this particular circuit works best with

also that the op amp sets an upper fre¬
quency limit and you have to save
enough “daylight” between the desired
cutoff frequency and the op amp’s cut¬
off frequency to have a passband left.

Sometimes the capacitor values of a
low-frequency active filter (high-pass or

HIGHPASS

OUTPUT

LOWPASS

OUTPUT

BANDPASS

OUTPUT

GND =
300Hz

-IOV*
100 Hz

Fig. J. Voltage-humble, state- ('(triable filter
is ideal for use in electronic music.

POPULAR ELECTRONICS

otherwise) get too large and too ex¬
pensive. This can be avoided by rais¬
ing the impedance of the circuit suit¬
ably. For instance, to raise the imped¬
ance by a factor of ten multiply all re¬
sistors by ten and divide all capacitors
by ten. These higher impedance cir¬
cuits tend to be more offset-sensitive
and should be used only when capaci¬
tor size is a serious problem.

Universal Filters. These are also
called state variable filters , and they
take three or four op amps per second-
order section, often in a quad package,
and use more resistors than the sim¬
pler circuits. However, they are vastly
better. Universal filters have three, and
sometimes more, simultaneous out¬
puts — low-pass, band-pass, high-pass,
and an optional notch output. They are
easily used with Q values of 500 or
more and don’t tax the frequency limits
of the op amps very heavily at all.
They easily realize ultra-low d values
without stability problems, they are
easy to voltage tune, and they are very
easy to switch from high-pass to band¬
pass to low-pass. About their only limi¬
tation is that a lot of parts are required
in systems with fancy filter responses
and multiple channels.

One universal filter is shown in Fig.
4. It is tuned by changing the R resis¬
tors or the capacitors. Once again, the
resistors should be identical and the ca¬
pacitors identical at all times. The Q or d
is set with the feedback resistor as
shown, while op amp gain at the cutoff
frequency should be 3Q or better. Note
that Q or d is easy to adjust indepen¬
dently. We can also design to different
values of circuit gain, but this involves
some non-obvious resistor calculations
on the first stage. For completely inde¬
pendent gain, damping, and frequency
another op amp can be added.

The low-pass, band-pass, and high-
pass outputs are progressively phase-
shifted by 90 degrees at the cutoff fre¬
quency. We can build quadrature art
systems by routing the LP and BP out¬
puts to a scope or plotter and inputting
interesting audio signals to the filter.
Since the circuit gain at resonance is Q,
be sure to limit input signals to a suitably
small size.

This circuit is really an analog com¬
puter that models a rusty pendulum.
With an infinite Q resistor (d = 0), there
is no damping (an oscillator). The Q re¬
sistor adds rust, or damping, to the pen¬
dulum.

The notch output shown has nothing

to do with the rest of the circuit and
can be left off if not desired. This out¬
put produces a zero output at reso¬
nance and a notch width proportional
to the circuit Q. The notch works by
summing the low-pass and high-pass
outputs which cancel at the resonance
frequency. If one of these input resis¬
tors is changed, the notch can be
moved either side of the resonance
frequency. This is a powerful class of
filters called Cauer or Elliptical filters
that strongly reject signals immediately
outside the passband.

Cascading. Two second-order sec¬
tions can be connected together to build
a fourth, and three to get a sixth, but the
damping and frequency values must be
watched if a useful overall response is to
be obtained. For instance, we’ve seen
how a maximally flat second-order sec¬
tion is built with a d value of 1 .41 . But
cascade three of these and what was a
-3 decibel cutoff frequency is now a
very droopy ^9 decibels and no longer
flat at all.

The Table shows the correct damp¬
ing and frequency values for high-pass
and low-pass filters of second, fourth,
and sixth order. The shapes selected
are for the best delay, the flatest ampli¬
tude, and a slightly peaked response.
These are called the Bessell, Butter-
worth, and One Decibel Chebycheff re¬
sponses. The cutoff frequency of all
values, defined to three decibels below
peak response is 1 kHz. The circuits
can be tuned to any other frequency
by the previous techniques we’ve
looked at, but all cascaded sections
must be changed by the same amount.
While five-percent resistor and capaci¬
tor values are usually more than ade¬
quate for these circuits, values correct
to one percent are indicated in the Ta¬
ble.

Voltage Control. To voltage control
a universal filter, replace the fixed or
variable frequency determining R resis¬
tors with something that looks like an
electrically variable resistor. One very
good choice is the CA3080 transcon¬
ductance amplifier, and a voltage con¬
trolled universal filter can be built as
shown in Fig. 5. This circuit provides a
linear voltage versus frequency control;
and frequency ranges of 100:1 and
even 1000:1 are possible with careful
design. One important design detail is
to keep the input voltage on the 3080
positive input to 100 millivolts or less
peak-to-peak for good linearity. O

Does your
computer
talk to you?

The intelligence of your
8080 system is only os greot
os its capacity to communicate.
Processor Technology's VDM-1
will function os a highly cogent
link to fhof intelligence. This
ultro-high speed output device
plugs into your Altoir or IM5AI
to provide tost, versatile
human interface. If generates
16 lines of display: 64 charac¬
ters each, botn upper and
lower cose. 1 024 bytes of
random access memory are
on the card. The VDM-1 scrolls
upwards or downwards, up to
a fop speed of 2000 lines per
minute! Any combination of
cursors (up to 1024) can be
displayed as black-on-whife or
vice versa — perfect for video
games. The VDM-1 will work
with any standard video moni¬
tor, or your own TV set can be
easily modified. The module
comes with free terminal mode
software, for teletype replace¬
ment when used with BASIC
or assemblers.

Our detailed VDM-1
Owner's Manual is available
for $4, refundable with
purchase of the VDM-1 .

Kit Price: (eff. 7/1/76): $199
(premium grade, low profile
1C sockets included).

!■■>■-

■i

Write Us,

about our other
plug-in modules,
compatible with
the 8800 system,

lechnology

6200-N Hollis Street
Emeryville, CA 94608

DECEMBER 1976

Product
Test Reports

ABOUT THIS MONTH’S HI-FI REPORTS

Technics’ new line of stereo receivers does not in general represent
any radical departure from the company’s past offerings . However ,
judging by the Model SA-5460, receiver performance has been refined
still further, to the point where this $400 receiver is capable of FM
and audio performance that should satisfy the needs of the critical
listener. Our tests revealed that the receiver’s rather impressive spec¬
ifications are completely realistic.

The long-awaited CD-4 phono cartridge from Shure Brothers has
finally made its appearance — the Model M24H. It is more than just a
very good CD-4 cartridge, however. It is also a first-rate stereo car¬
tridge whose “trackability” matches that of the company’s Model
M95ED stereo cartridge and comes close to rivalling the top-of-the-
line V-15 Type III in stereo performance . Best of all is the fact that
the M24H is moderately priced, costing just a few dollars more than
the better stereo cartridges .

— Julian D. Hirsch

TECHNICS MODEL SA-5460 STEREO RECEIVER

Top-notch performance in medium-priced range.

marks linearly spaced at 500-kHz inter¬
vals. The lower half of the dial cutout is
finished in black, except for the illuminat¬
ed signal-strength and center-channel
tuning meters and a red stereo indica¬
tor light.

At the lower left of the panel are the
power pushbutton switch and phones
jack, followed by pushbutton switches
for two pairs of speaker systems. The
bass and treble controls are lightly de-
tented at 1 1 positions and the balance
control is center detented. The high and
low audio filters are pushbutton con¬
trolled. The volume control is followed
by a row of five pushbutton switches for
loudness compensation, fm muting*
stereo/mono mode selection, and tape
monitor functions for two tape decks.
(A tape can be directly dubbed from one
to the other tape deck.) The selector
switch has positions for am, fm auto,
phono, and aux. Finally, the large tun¬
ing knob operates a very smooth fly¬
wheel tuning mechanism.

On the rear apron of the receiver is a 4
ch mpx out jack that provides a detect¬
ed but unprocessed signal for use with a
future discrete 4-channel FM decoder.
Insulated binding posts are used for the
300- and 75-ohm FM and long-wire AM
antenna input terminals and the speaker
output terminals. Covered fuses protect
the output transistors. There are two
accessory ac outlets on the rear apron,
one of which is switched. The ferrite-rod
AM antenna is inside the receiver and is
not adjustable.

• #• ^ frj'i 0'

5460 is one of a
new line of stereo
receivers from
Technics by Pan¬
asonic. Its differential, completely direct-
coupled audio amplifiers are rated at 65
watts/channel into 8-ohm loads with
less than 0.1% distortion over a frequen¬
cy range of 20 to 20,000 Hz. The com¬
plementary output transistors are also
direct-coupled to the speaker systems
driven by the amplifier section.

The phono preamplifier circuit em¬
ploys integrated circuits, with precision
components in the RIAA feedback
equalizing network. The FM tuner sec¬
tion has a seven-stage i-f amplifier
whose three two-element filters have
uniform group delay characteristics. The
74

i-f section, in conjunction with a phase-
locked-loop multiplex demodulator, con¬
tributes to the receiver’s rated channel
separation of 35 to 45 dB across the au¬
dio range.

The receiver is furnished with a simu¬
lated wood-grain cabinet. It measures
about 1 93A" W x 1614" Dx 574" H (50.2
x 42 x 15 cm) and weighs 31 lb (14 kg).
List price is $399.95.

General Description. The receiver s
styling is quite similar to the Technics
equipment of last year. The pale gold,
satin finished aluminum front panel has
a large dial window. The various con¬
trols and switches are arranged in a sin¬
gle row across the bottom of the panel.
Half the dial area is devoted to the cali¬
brated scales, with the FM calibration

Laboratory Measurements. Fol¬
lowing the FTC preconditioning period of
operating amplifiers for one hour at one-
third the rated output power, the receiv¬
er’s amplifiers clipped at 87 watts/chan¬
nel into 8-ohm loads, 110 watts into 4
ohms, and 54 watts into 1 6 ohms. These
tests were made with a 1000-Hz input
signal. The THD measured 0.01% be¬
tween 0.1 and 1 watt. It increased slowly
to 0.02% at 20 watts, was 0.03% at 30
watts, and hit 0.1% at 75 watts. The in¬
termodulation (IM) distortion was be¬
tween 0.03% and 0.05% from 0.1 to 40
watts. It reached 0.1% at 60 watts.

At the rated output of 65 watts, the
distortion was less than 0.08% between
20 and 20,000 Hz and was typically
about 0.04%. At half and one-tenth pow¬
er, the distortion was substantially less.
At any normal playing level and frequen¬
cy, the distortion can be expected to be
between 0.15% and 0.02%.

An input of 50 mV at the aux jacks
drove the amplifier to a reference 10-
watt output, with the noise level 75.5 dB
POPULAR ELECTRONICS

1-kHz total harmonic and 60/7000-Hz IM distortion. Harmonic distortion at three power levels .

below 10 watts. The phono sensitivity
was 0.82 mV, with a 70-dB S/N ratio.
The phono circuits overloaded at a very
safe 125 mV input signal level.

The Baxandall tone controls had a
sliding turnover frequency in the bass
range and a treble response hinged at
about 2000 Hz. At intermediate settings,
the bass control could give a substantial
modification of the response below 200
Hz, with negligible effect at higher fre¬
quencies. The loudness compensation
became effective only at fairly low set¬
tings of the volume control and boosted
only the low frequencies. The high and
low filters had gradual 6-dB/octave
slopes, with the -3-dB responses at
100 and 6000 Hz. The RIAA phono
equalization was accurate to within ±0.5
dB from 50 to 20,000 Hz. Unlike the
case with most phono preamplifiers, the
frequency response was boosted slight¬
ly at the high end of the range by the in¬
teraction with the cartridge’s inductance.
However, the effect was small, amount¬
ing to only 1 dB at 1 5,000 Hz and 3 dB at
20,000 Hz.

The FM tuner section lived up to the
promise of the receiver’s specifications.
The IHF sensitivity was 11 dBf (2.0 pA/)
in mono, while in stereo it was deter¬
mined by the stereo switching threshold
of 23 dBf (8 p.V). In mono, 50 dB of qui¬
eting was achieved at 15 dBf (3.0 pA/),
with 0.7% distortion, while in stereo it
was 37 dBf (40 pA/), with 0.37% distor¬
tion. The S/N at 65 dBf (1000 pA/) was
70 dB in mono and 68 dB in stereo, and
the respective distortion measurements
were 0.083% and 0.15%, well below the
rated 0.15% and 0.25%. With the L-R
modulation called for by the IHF stand¬
ards, the THD was 0.63% at 100 Hz,
0.14% at 1000 Hz, and it was 0.32% at
6000 Hz.

The frequency response of the FM
tuner was almost ruler flat from 30 to
10,000 Hz and down a mere 0.8 dB at
15,000 Hz. The channel-separation
characteristic was also very flat, mea¬
suring 40 dB across most of the audio
range and still a very good 33.5 dB at 30
Hz and 35 dB at 1 5,000 Hz. The capture
ratio was an excellent 1.1 dB. AM rejec¬

tion was 74 dB at 65 dBf but reduced to
57 dB at 45 dBf. (It is rated at 55 dB.)

The tuner’s image rejection was 54.8
dB, which was close to the rated 53 dB.
Alternate-channel selectivity was 5.3
dB. The muting threshold was 22 to 24
dBf (7 to 9 p.V). In spite of the very flat
FM frequency response, the 19-kHz pi¬
lot carrier was suppressed a very good
70 dB (rated 65 dB). The hum was mea¬
sured to be 65 dB down.

The AM frequency response was re¬
stricted at both ends of the spectrum.
The response was down 6 dB at 160
and 3500 Hz.

User Comment. If this receiver had
been offered for sale only a couple of
years ago, it would have been outstand¬
ing at any price. The constant improve¬
ment in IC’s and other electronic compo¬
nents has contributed in great measure
to the creation of this fine receiver,
whose relationship with its predecessors
must be regarded as evolutionary rather
than revolutionary. This is not intended
to denigrate the new receiver in any

sirfttHmriimrmTtisaia} n

TFPMN M (tape-output jacks) -

' 19 • ii iiiiii:

ro -50dB QUIETING SENSITIVITY
;MONO: IBdB»(3.0|iV)AT 0.7% THD
ISTEREO: 37dBf (40pV) AT 0.37%THD

jTjTIIi 11 [f I IlilLill m j : [Tl :

If H I

INPUT dBf

- MONO [

- STEREO

Frequency response and crosstalk
averaged for both channels in
stereo FM of Technics receiver.

Noise and sensitivity curves for FM section.

DECEMBER 1976

way. It is an excellent product whose
handling and freedom from undesirable
side effects are only too easy to take for
granted.

The receiver’s' stereo FM perfor¬
mance is so close to ideal that a signifi¬
cant improvement would be difficult to
imagine. There are no program sources
whose frequency response, flatness,
distortion, and channel separation can

come even close to those of the Model
SA-5460. Although not quite in the “su¬
per-power” category, the Model SA-
5460 is actually a very powerful re¬
ceiver, capable of doing justice to almost
any home speaker system in a large lis¬
tening room. Obviously, the receiver’s
distortion and other characteristics are
consistent with the requirements of a de¬
luxe receiver.

Our positive reaction to this receiver
was enhanced by two factors that are of¬
ten overlooked in receiver design but
which we consider to be very important:
the FM dial calibration is both legible
and accurate, and the muting circuit is
positive yet free of the noise bursts that
sometimes accompany tuning on and off
a station.

CIRCLE NO. 102 ON FREE INFORMATION CARD

SHURE MODEL M24H ALL-FORMAT PHONO CARTRIDGE

Plays stereo/matrixed and discrete 4-channel.

playback of both stereo/matrixed quad¬
raphonic and discrete 4-channel CD-4
records without compromising any for¬
mat. The new cartridge is not only de¬
signed to be compatible with all modern
record formats, but it tracks at lower sty¬
lus pressure and is reasonably priced.

The Model M24H physically resem¬
bles Shore’s Model M95ED stereo car¬
tridge, with a hinged stylus guard at¬
tached to its removable stylus assembly.
Price is $74.95.

General Description. The extended
frequency response of the Model M24H
has been achieved in several ways.
First, the winding inductance has been
reduced (compared to stereo car¬
tridges). Second, the moving mass of
the stylus has been reduced to 0.39 mg,
which is claimed to be lower than the
mass of any other CD-4 cartridge on the
market. Finally, a new “hyperbolic” dia¬
mond stylus with radii of 0.3 and 0.7 mil
was developed, the edges of which are
shaped to contact a larger portion of the
groove walls on the record than is possi¬
ble with a conventional elliptical stylus.

The cartridge is designed to track at
stylus forces of between 1 and 1.5
grams, with 1.25 being the optimum.
The typical frequency response curve
published by Shu re illustrates an essen¬
tially flat response up to about 10,000
Hz. The curve rises to a broad maximum

of about +5 dB in the region between
20,000 and 30,000 Hz before returning
to the midrange level at 50,000 Hz.
Channel separation is specified at nomi¬
nally 22 dB at 1000 Hz, while the output
is rated at 3 mV at 5 cm/s peak velocity.

Shure’s “trackability” data for the car¬
tridge indicates that the Model M24H is
essentially equivalent to the company’s
Model M95ED stereo and not far behind
the top-of-the-line Model V-15 Type III
stereo cartridges in this important pa¬
rameter. The company candidly states
that the stereo-only listener who has no
plans for a discrete 4-channel record¬
playing capability might as well choose
the lower-priced Model M95ED or go to
the V-15 Type III cartridge if his budget
permits. However, if there is any possi¬
bility of future conversion to CD-4, the
Model M24H is an ideal choice of car¬
tridges. It combines the best of both
worlds at a price that is intermediate be¬
tween the two top stereo cartridges.

Because of the lower inductance of
the coils, the optimum stereo load capa¬
citance of the cartridge is less than that
of other Shure cartridges. Shure recom¬
mends 100 to 250 pF of capacitance in
parallel with a 47,000-ohm resistance,
as opposed to the 400 to 500 pF prefer¬
able for the Models M95ED and V-15

Type III cartridges. For CD-4 operation,
the optimum load for the new cartridge is
the 100,000-ohm input resistance that is
standard for all CD-4 demodulators, in
parallel with 100 pF capacitance.

Laboratory Measurements. We

tested the cartridge in the tonearm of a
Dual Model 701 record player, using the
recommended loads for measurements
in the audio and carrier ranges. The car¬
tridge tracked the high-level, low-fre¬
quency test records nicely at only 0.9
gram, but there was considerable wave¬
form distortion on the 1000-Hz, 30-cm/s
tones of the Fairchild 101 record at 1.25
grams and still some peak clipping at 1 .5
grams. The 300-Hz tones of the German
High Fidelity Institute record were play¬
able at the 60-micron level. An increase
to 1 .25 to 1 .5 grams did not make a sig¬
nificant improvement. We used 1.25
grams for our subsequent tests and lis¬
tening evaluation.

The output from the cartridge was 2.7
mV at 3.54 cm/s velocity. The vertical
stylus angle measured 24°. IM distortion
was extremely low, measuring 0.6% to
1%, at velocities from 6.7 to 18 cm/s,
using the Shure TTR-102 test record.
The IM rose steeply at high velocities,
reaching 5% at 22 cm/s and definitely

Response and channel separation in audio range.

POPULAR ELECTRONICS

n h

1 i

Results of square-wave
tests with CBS STR-112 record .

mistracking at the much higher levels.

The repetition rate distortion of the
tone bursts on the Shure TTR-103 test
record was also exceptionally low,
matching the Model M95ED cartridge in
this test and surpassing just about every
other cartridge we have tested. The dis¬
tortion measured 0.6% from 15 to 22.5
cm/s and only 0.8% at 30 cm/s. The
low-frequency resonance in the Dual
tonearm was at about 9 Hz.

Using the CBS STR100 test record,
our frequency response measurements
in the audio range were flat to within ±1
dB up to about 10,000 Hz, rising to +7
dB at 20,000 Hz. Channel separation
was 20 to 30 dB in the midrange. (The
two channels were not identical in this
respect.) One channel maintained out¬
standing separation all the way to
20,000 Hz, where it measured 28 dB,
while the other channel was a very good
20 dB at this frequency.

We used the JVC TRS-1005 record to
measure the cartridge’s response in the
carrier-frequency band. It was almost
identical to the curve published by
Shure, flat up to 10,000 Hz and rising to
between +6 and +7 dB in the range be¬
tween 20,000 and 30,000 Hz. At 50,000
Hz, the output was the same as at 1000
Hz. On one channel, the separation was
15 to 20 dB all the way up to 50,000 Hz,

while on the other channel it was 8 dB at
40,000 Hz and 2 dB at 50,000 Hz.

In stereo, the subjective trackability
was judged with the aid of Shure’s Audio
Obstacle Course— Era ill test record. At
1 .25 grams, the cartridge played every
portion of this record without difficulty,
except for a trace of “sandpaper” quality
at the highest level of the sibilance sec¬
tion. Very few cartridges, stereo or
CD-4, can do as well, let alone match
this performance.

We connected the cartridge to a Tech¬
nics Model SH-400 demodulator for
playing CD-4 records. Not surprisingly,
the cartridge acquitted itself admirably.
Most of the records that have been
prone to “shattering” distortion with oth¬
er cartridges delivered clean, well-
separated 4-channel sound with the
Shure cartridge. In the few instances
where distortion was heard, the same
effect has been observed with every oth¬
er cartridge. It can, therefore, be as¬
sumed that the record is at fault.

User Comment. Our tests and use of
the Model M24H confirmed Shure’s
claim that this is a “no compromise" car¬
tridge for playing stereo/matrixed and
CD-4 records. We could find no audible
fault with the cartridge in our lab and lis¬
tening tests. While it does have an ac¬
centuated response in the uppermost
audible octave from 10,000 to 20,000
Hz, this does not give the cartridge an
audibly bright sound. Even if the car¬
tridge should sound a trifle crisp, most
good amplifier tone controls should be
able to correct the response.

As a CD-4 player, this cartridge is as
good as any we have used. There are
one or two CD-4 cartridges that can
match the performance of the Model
M24H when operated at 1 gram, but the
difference between 1 .25 and 1 .0 gram is
negligible. Not so negligible is the price

358 llfeys
ToSaveOn
Instruments,
Citizens Band,
Burglar Alarms,
Automotive &
Hobby
Electronics!

The more you know about
electronics, the more you’ll
appreciate EICO. We have a wide
range of products for you to
choose from, each designed to
provide you with the most
pleasure and quality performance
for your money. The fact that
more than 3 million EICO products
are in use attests to their quality
and performance.

“Build-it-Yourself” and save
up to 50% with our famous
electronic kits.

For latest EICO Catalog and name
of nearest EICO Distributor, check reader
service card or send 500 for fast first
class mail service.

EICO— 283 Malta Street,

Brooklyn, N.Y. 11207

Leadership in creative electronics
since 1945.

Response and channel separation in carrier- frequency band.

DECEMBER 1976

CIRCLE NO. 25 ON FREE INFORMATION CARO

difference between the Shure and any
other cartridge of comparable quality.
Based on a list-price basis, the Shure
cartridge saves the user $25 to $100 on

the purchase of a new CD-4 cartridge,
while supplying stereo/matrixed repro¬
duction capability. The Model M24H
strikes us as being a fine value as a uni¬

SBE MODEL 32CB FORMULA D TOUCH/COM CB TRANSCEIVER

Mike contains LED channel display and squelch , volume , and channel controls.

THE SBE Model 32CB Formula D
Touch/Com AM CB mobile trans¬
ceiver employs the latest in digital fre¬
quency synthesis to provide full 23-
channel coverage. What sets this trans¬
ceiver apart from most others on the
market is that the squelch, volume,
and channel selector controls and a
pair of red LED numeric displays are on
the microphone. This puts the
most-used controls right at the opera¬
tor’s fingertips and permits the trans¬
ceiver to be located in an out-of-the-way
place.

Electronically and in its performance,
the transceiver is similar to the SBE For¬
mula D reviewed in the October 1975 is¬
sue of Popular Electronics. It in¬
cludes a switchable automatic noise lim¬
iter (nl), audio tone control, s/rf me¬
ter, DELTA TUNE control, DISTANCE/
local switch, pa operation, and a trans¬
mitter-on indicator. Operation can be
from any 11.7-to-1 5. 9-volt, negative- or
positive-ground, dc power source capa¬
ble of delivering up to 2.5 amperes of
current. The power-supply section fea¬
tures reverse-polarity protection, voltage
regulation, and a line filter.

The transceiver measures 9 ¥a” x
6%"D x 2Vi"H (24 x 17 x 6.4 cm). It re¬
tails for $289.95.

Technical Details. The receiver sec¬
tion employs double conversion to i-f’s
at 10.695 MHz and 455 kHz. A dual-gate
FET is used for the r-f amplifier, which is
followed by the first and second mixers,
455-kHz ceramic filter, two bipolar tran-
78

sistor i-f stages, diode detector, age,
squelch, series-gate anl, two audio
stages, and a class-B power-output
stage. The last stage is also used for PA
operation and for modulating the trans¬
mitter.

The digital frequency synthesis sys¬
tem uses a phase-locked loop (PLL) 1C.
(For detailed information on how the fre¬
quency synthesizer works, see October
1975 Product Test Report for the For¬
mula D transceiver.)

The design of the transmitter section
is conventional. It uses a dual-gate FET
mixer and pre-driver, driver, and r-f pow¬
er output amplifiers. A double-pi output
network provides matching to 50-ohm
loads and spurious-response attenua¬
tion, augmented by a 54-MHz TV! trap.
Automatic modulation control (amc) is
designed into the circuit. Antenna trans¬
fer is accomplished electronically with a
diode switch.

Overall Performance. The perfor¬
mance of the transceiver was quite simi¬
lar to that of its predecessor! the Formu¬
la D. Our measurements indicated a re¬
ceiver sensitivity of 0.3 to 0.5 pV, de¬
pending on the setting of the tone con¬
trol, for a 10-dB (S + N)/N with 30%
modulation at 1000 Hz. Image and i-f
signal rejection were 80 dB, while un¬
wanted spurious-signal responses were
a minimum of 60 dB, except for signals
near 26 MHz, where the figure was 50
dB. Adjacent-channel rejection was
measured at 50 dB.

The age held the audio output level to

versal phono cartridge. It certainly
passed all of our tests easily for both 4-
channel and stereo use.

CIRCLE NO. 103 ON FREE INFORMATION CARD

within 7.5 dB with an r-f input variation of
80 dB at 1 to 10,000 p.V. At 1 to 10 pA/,
the output remained within 4 dB. The
meter indicated S9 with a nominal input
signal level of 30 pA/. The squelch
threshold range was 0.25 to 10,000 pA/.

The maximum sine-wave audio output
at the onset of clipping was 3 watts at
7% THD, using a 1000-Hz test signal
and taking the measurement with an 8-
ohm load. The overall 6-dB response,
including that of the i-f passband, was
425 to 3500 Hz. Good sound quality was
obtained from the bottom-facing speak¬
er. The effectiveness of the anl system
was fine. It permitted readability of a
0.3-p.V signal in the presence of
1000-p.V and more peaks of most exter¬
nal noise pulses.

The local/distance switch dropped
the r-f gain by about 30 dB when set to
the local position. However, the good
signal-handling capabilities of the trans¬
ceiver made it seldom necessary to use
the local position in the presence of
strong signals.

Operating the transceiver from a 1 3.8-
volt source, the transmitter carrier output
measured slightly greater than 4 watts.
Increasing the microphone input level by
10 dB over that required for 50% modu¬
lation held the r-f envelope to a sine
wave at 100% modulation with 4.25%
THD while using a 1000-Hz test tone. A
15-dB increase introduced clipping of
both positive and negative peaks with
overmodulation on the latter. The THD
in this case was 12.5% with adjacent-
channel splatter down 50 dB. The over¬
all signal level with voice operation
allowed full modulation while holding the
splatter to an excellent 55 to 60 dB
down. The 6-dB audio response was
200 to 6500 Hz.

The frequency tolerance on all chan¬
nels was essentially the same, holding
to within 0.0001%. The current drain
was a little higher than usual. On re¬
ceive, the drain was between 1.0 and
1 .75 amperes, while on transmit it was
1 .7 to 2.25 amperes. The power supply
used during these tests was rated at
13.8 volts.

User Comment. The microphone had

POPULAR ELECTRONICS

the customary push-to-talk switch button
on the left side of its case. The volume
and squelch controls are thumbwheel
types and are located on the right side of
the case. These controls have numerals
on their edges, requiring the user to ro¬
tate the mike to observe the numerals.

Two square buttons located at the top
of the mike’s housing are for selecting
the CB channel desired. The button on
the left is marked up for an upward
numerical progression through the
channels. The button on the right, la¬
belled dn, is for a downward progres¬
sion. Every time either button is momen¬
tarily depressed and released, the sys¬
tem steps one channel. By holding down

CIRCLE NO. 104 ON

a button, the channels can be continu¬
ously advanced up or down automatical¬
ly until the desired channel is reached.
When the transceiver is first turned on,
Channel 1 always comes up first. Pro¬
gression through the channels can be
made in either direction at anytime.

The seven-segment LED numeric dis¬
plays used for indicating the channel are
located at the lower center of the front of
the microphone’s case.

Taken as a whole, the Touch/Com
transceiver provides convenient and
safe handling as well as fine perfor¬
mance and the latest in frequency syn¬
thesis. Its very up-to-date design is well
suited for any mobile application.

E INFORMATION CARD

SENCORE MODEL TF40 PORTABLE TRANSISTOR TESTER

Checks in - and out-of-circuit devices without setup information .

S ENCORE’S new Model TF40
“Pocket Cricket” is a portable, com¬
pact in-circuit and out-of-circuit transis¬
tor and FET tester. It employs the same
basic test principles used for the compa¬
ny’s more expensive ac-only Cricket
testers and does not require set-up in¬
formation to test any device.

The Pocket Cricket provides good/
bad gain tests, meter-calibrated leak¬
age, and transistor basing identification.
Additionally, an audible test tone sounds
if the device under test has good gain.
The tester is equally convenient to use
in the field on battery power and on the
test bench on battery or line power, the
latter with an optional power adapter.
For fast in-circuit tests, there is also
available an optional “Touch Test
Probe”No. 39G85.

The transistor tester measures 6"L x
4"W x VA"D (15.2 x 10.2 x 3.2 cm)
and weighs 14 oz (0.39 kg). The Model
TF40 tester is priced at $98; the optional
No. PA202 power adapter and No.
39G85 Touch Test Probe, $9.95 each.

General Description. The tester is
designed for rapid checking of transis-
DECEMBER 1976

tors and diodes even by persons with lit¬
tle or no technical knowledge. The con¬
trol complement, therefore, has been
limited to just three function switches
and a rotary thumbwheel potentiometer.
The device condition display is a 2V£"
(6.4-cm) wide meter movement whose
scale is broken up into bad and good
sections for gain and battery-check indi¬
cations. It is calibrated from 0 to 2500
jxV for leakage measurements. A built-in
loudspeaker emits a tone during the
tests when gain is “good.”

A large 12-position “permutator”
switch occupies the major portion of the
instrument’s front panel. Arranged along
the bottom of the panel are the power
on/off and batt check switch, lead
id control pot, and id/gain/leak function
switch. Exiting through the bottom of the
instrument’s case is a cable whose three
conductors are terminated in color-cod¬
ed E-Z Hook® connectors. A single 9-
volt battery, housed in a compartment at
the top-rear of the case, provides the
power necessary for testing.

Connections to the device under test
are made via the E-Z Hooks. It is not
necessary to know the basing or type of
device being tested. You simply connect
the E-Z Hooks at random to the device’s
leads. Then, setting the power switch to
on and function switch to gain and rotat¬
ing the permutator switch through its po¬
sitions will give a good/bad gain indica¬
tion and simultaneously identify the de¬
vice as being npn (or n-channel) or pnp
(or p-channel). At one or two positions of
the permutator switch, the built-in
speaker will emit a tone, assuming the
device under test is good. Depending on
whether the “good” positions of the
switch are located in the n or the p la-

The Best
Way To Show,
YouWhal
You’ll Get I
Out Of An U
Empire p
Phono 0
Cartridge
Jsto ®
ShowYou_ ,
What GoesW

Already your system
sounds better.

of phono cartridges. ^ J

Eacn one has slightly

different perform-

ance characteristics i IdSOByi

which allow you to %

choose the cartridge |r

most compatible to

your turn tame. jL

There are, how- fcs.
ever, certain advan-
tages, provided by C
Empire’s unique
design, that apply to Jr

all our cartridges.

One is less wear on fJII 7y
your records. Unlike
other magnetic cart-
ridges, Em pire’s
moving iron a.
design allows the
diamond stylus to C

float free of its magnets and
coils, imposing much less weight on
your record’s surface and insuring
longer record life.

Another advantage is the better
channel separation you get with Empire
cartridges. We use a small, hollow iron
armature which allows for a tighter fit in
its positioning among the poles. So,
even the most minute movement is
accurately reproduced to give you the
space ana depth of the original record¬
ing.

Finally, Empire uses 4 coils, 4 poles,
and 3 magnets (more than any other
cartridge) for better balance and hum
rejection.

The end result is great listening.
Audition one for yourself or write for
our free brochure, “Hew To Get The
Most Out Of Your Records”. After you
compare our performance specifica¬
tions we think you’ll agree that, for the
money, you can’t do better than Empire.

Empire Scientific Corp.

Garden City, New York 11530

i/PIEE

belled area of the dial ring, the device is
either an n type or a p type.

Once the gain/type test is performed,
the function switch goes to the leak po¬
sition and the permutator switch is rotat¬
ed through only the six positions of the
identified type. The meter then indicates
the six possible leakage conditions for
the transistor.

Finally, the permutator switch is set to
either of the two “good” positions and
the function switch to id. Then the lead
id control is adjusted until the test tone
ceases in either position, at which time
the transistor is known to be bipolar and

its basing is identified by matching the
three-letter color code on the dial ring
with the legend on the switch pointer. If
the tone does not cease in either posi¬
tion of the permutator switch, the device
is a FET, and its basing is also identified
in the same manner.

Testing diodes is quite simple. Only
the red and yellow E-Z Hooks are used
here. The function switch is set to leak
and the permutator switch first to the top
two and then the bottom two positions. A
good diode will cause the meter’s point¬
er to deflect far up-scale in either the two
upper or two lower, but not both sets of

positions. A good diode will cause the
test tone to sound in either the two upper
or the two lower positions of the per¬
mutator switch. If the diode is open, no
tone will be heard; if it is shorted, a tone
will be heard in all four positions. For a
good diode, the position of the permuta¬
tor switch and color-code identification
of the E-Z Hooks will identify the cath¬
ode and anode.

All tests can be performed in- or out-
of-circuit. For in-circuit tests, the optional
Touch Test Probe is a real time saver.
This probe connects to the tester via the
E-Z Hooks according to a color-coding
scheme. At the test end of the probe are
three, also color-coded, sharp test
points that contact the transistor’s con¬
nection pads. The test points are pivota¬
ble to permit use of the probe on a wide
variety of transistor basing and spacing
configurations.

User Comment. The Pocket Cricket
is a delight to use. Its proven gain-test
circuit that detects a device’s ability to
amplify and invert a safe-level test sig¬
nal, combined with a leakage test cali¬
brated in microamperes, provides the
degree of test accuracy needed by a
service technician or experimenter.
Combined with the in-circuit/out-of-cir-
cuit test capability and no set-up require¬
ment, it makes testing transistors, di¬
odes, and FET’s easy and fast. In fact,
we were testing and sorting loose tran¬
sistors at a rate of one about every 90
seconds or so.

Small size and battery or ac line (with
an adapter) power plus a ruggedized
case add to the tester’s worthiness. Of
course, the Pocket Cricket is not the
type of analyzer that an enginerring
technician or electronics engineer would
be likely to require for complete parame¬
ter tests. Nor does it reliably test
high-frequency oscillators. But for what
it does, and at its price, this is an impres¬
sive instrument. It is made all the better
when used with the optional Touch Test
Probe and power accessory. The power
accessory can serve both as a battery
eliminator and recharger, the latter when
the standard 9-volt battery is replaced
by rechargeable nickel-cadmium cells.

Built into the tester’s case is a swing-
out tilt stand that raises the Pocket
Cricket to a convenient viewing angle on
the work bench. Another nice touch is
the four rubber feet on the bottom of the
instrument case. Made of non-skid plas¬
tic material, the feet prevent the instru¬
ment from sliding around on a busy elec¬
tronics workbench.

CIRCLE NO. 105 ON FREE INFORMATION CARD

handid

hantlic USA, Lnc.. 14560 NW 60th Ave , Miami Lakes, FL 33014

THE ORANGE EQUIPMENT KNOWN FOR
PROFESSIONAL QUALITY THE WORLD OVER

CIRCLE NO. 35 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

A cartridge in a pear tree.

A gift of the Shure V-15 Type III
stereo phono cartridge will earn
you the eternal endearment of
the discriminating audiophile
who receives it. What makes the
V-15 such a predictable Yuletime
success , of course, is its ability
to extract the real sound of
pipers piping, drummers
drumming, rings ringing, et
cetera, et cetera. In test reports
that express more superlatives
than a Christmas dinner, the
performance of the V-15 Type III
has been described as “...a
virtually flat frequency
response. . . Its sound is as
neutral and uncolored as can be

desired.” All of which means
that if you're the giver, you can
make a hi-fi enthusiast
deliriously happy. ( If you 'd like
to receive it yourself, keep your
fingers crossed!)

Shure Brothers Inc.

222 Hartrey Ave.,

Evanston, IL 60204

In Canada:

A. C. Simmonds ed Sons Limited

TECHNICORNER

MODEL V-15 TYPE III

Tracking Force Range: 3A to 1 *4 grams

Frequency Response: 10 to 25,000 Hz

Output: 3.5 mV per channel at 1 KHz, Scmfsec

peak recorded veloci ty

Typical Tracking (in cmlsec peak recorded

velocity at 1 gram in a Shure- SME Tone Arm):

400 Hz . 26 cmlsec

1,000 Hz . 38 cmlsec

5,000 Hz . 35 cmlsec

1 0,000 Hz . . 26 cmlsec

Channel Separation (Minimum): 25 dB at
1 KHZ; 15 dB at 10 KHz
Stylus: Model VN35E Biradial Elliptical , 5 x
18 microns (.0002 x .0007 inches)

Also available: Model V-15 III G with the
VN3-G Spherical stylus, 15 microns (.0006
inches)

Model VN78E Biradial Elliptical stylus, 13 x
63 microns (.0005 x .0025 inches) for mono
78 rpm.

Manufacturers of high fidelity components, microphones, sound systems and related circuitry.

DECEMBER 1976

CIRCLE NO. 58 ON FREE INFORMATION CARO

Advanced Electronics

Should your
career in
electronics
go beyond

TV repair?

CREI prepares you at home
for broader and more advanced
opportunities in electronics-
plus offers you special arrangements
for engineering degrees

There is no doubt television repair can
be an interesting and profitable career
field. TV repair, however, is only one of
the many career areas in the fast growing
field of electronics.

As an indication of how career areas
compare, the consumer area of electron¬
ics (of which TV is a part) makes up less
than one -fourth of all electronic equip¬
ment manufactured today. Nearly twice
as much equipment is manufactured for
the communications and industrial fields.
Still another area larger than consumer
electronics is the government area. That
is the uses of electronics in such areas as
research and development, the space
program, and others.

Just as television is only one part of
the consumer field, these other fields of
electronics are made up of many career
areas. For example, there are computer
electronics, microwave and satellite
communications, cable television, even
the broadcast systems that bring pro¬
grams to home television sets.

As you may realize, career oppor¬
tunities in these other areas of electron¬
ics are mostly for advanced technical
personnel. To qualify for these higher
level positions, you need college-level
training in electronics. Of course, while
it takes extra preparation to qualify for
these career areas, the rewards are
greater both in the interesting nature of
the work and in higher pay. Further¬
more, there is a growing demand for
personnel in these areas.

Unlike most other home study schools,
CREI programs are devoted exclusively
to preparing you for careers in advanced
electronics. All of CREI programs are
college level. And CREI gives you both
theory and practical experience in ad¬
vanced electronics.

Unique Design Lab

A unique feature of CREI training is its
Electronic Design Laboratory Program,
which trains you to actually design cir¬
cuits. It also helps you understand the
theories of advanced electronics and
gives you extensive practical experience
in such areas as tests and measurements,
breadboard ing, prototype construction,
circuit operation and behavior, charac¬
teristics of electronic components and
how to apply integrated circuits.

POPULAR ELECTRONICS

Career Training at Home

Only CREI offers this unique Lab
Program. It is a complete college lab
and, we believe, better than you will find
in most colleges. The “Lab" is one of
the factors that makes CREI training
interesting and effective. And the pro¬
fessional equipment in this program be¬
comes yours to keep and use throughout
your professional career after you com¬
plete the training.

Engineering Degree

CREI offers you special arrangements
for earning credit for engineering de¬
grees at certain colleges and universities
as part of your home study training pro¬
gram. An important advantage in these
arrangements is that you can continue
your full time job while “going to college"
with CREI. This also means you can
apply your CREI training in your work
and get practical experience to qualify
for career advancement.

Wide Choice of Programs

CREI gives you a choice of specializa¬
tion in 14 areas of electronics. You can
select exactly the area of electronics
best for your career field. You can spe¬
cialize in such areas as computer elec¬
tronics, communications engineering,
microwave, CATV, television (broad¬
cast) engineering and many other areas
of modem electronics.

FREE Book

In the brief space here, there isn’t room
to give you all of the facts about CREI
college-level, home study programs in
electronics. So we invite you to send for
our free catalog (if you are qualified to
take a CREI program). The catalog has
over 80, fully illustrated pages describ¬
ing your opportunities in advanced elec¬
tronics and the details of CREI home
study programs.

Qualifications

You may be eligible to take a CREI col¬
lege-level program in electronics if you
are a high school graduate (or the true
equivalent) and have previous training
or experience in electronics. Program
arrangements are available depending
upon whether you have extensive or
minimum experience in electronics.

Send for this FREE Book
describing your opportunities
and CREI college-level
programs in electronics

Mail card or write describing qualifications to

CAPITOL

RADIO

ENGINEERING

INSTITUTE

McGraw-Hill Continuing Education Center
3939 Wisconsin Avenue Northwest
Washington, D.C. 20016

Accredited Member National Home Study Council

Gl Bill

CREI programs
are approved
for training of
veterans and
servicemen under
the GJ. Bill .

r:mfe

DECEMBER 1976

i— ■ jJ 1U Inside Basic

Electronics

CAPACITORS AND RF CIRCUIT, Part 2

By Sol D. Prensky

AS WE mentioned last month, a ca¬
pacitor exhibits an opposition to the
flow of ac that decreases as the capaci¬
tance or frequency of the applied signal
(or both) is increased. This capacitive
reactance is measured in ohms, but is
not a true resistance because it does not
comsume power and dissipate it as
heat. But you might find it helpful at this
point to consider the capacitor as a
“phantom” resistor. The exact amount
of reactance that a capacitor exhibits at
a given frequency is found by using the
equation Xc=1/(2TrfC), where Xq is in
ohms, f (frequency) in hertz, and C (ca¬
pacitance) in farads. For example, a
1-p,F capacitor has 159.2 ohms of reac-

o 1 o

Fig . 1. An RC low-pass filter.

tance at 1000 Hz, and 0.1592 ohms at 1
megahertz.

Frequency Response. One of the

key terms used in discussing RC combi¬
nations is frequency response. Refer¬
ring to Fig. 1 , this concept is used to re¬
late the input signal to the output signal.
In descriptions of such circuits, we often
come across such terms as the corner
or cut-off frequency , or the break, half¬
power or -3-dB point. They all refer to a

Vc*V0UTt 0.707

Fig. 2. Voltage vectors.

particular frequency that is a mathemati¬
cally convenient reference point.

Viewing the circuit from the input, the
network looks like a series combination
of resistor R and capacitive reactance

Xq. These two behave somewhat like a
voltage divider — the voltage drop across
each element varies with its relative
amount of resistance or reactance. If Xq
is much greater than R, most of the input
voltage appears across the capacitor.
Thus, the output voltage is an apprecia¬
ble fraction of the input. At higher fre¬
quencies, less and less voltage appears
across the capacitor, while most of the
input is dropped across the resistor, re¬
ducing the output voltage. (Assume
these voltages are measured with a
high-impedance ac voltmeter to avoid
loading down the voltage divider, as dis¬
cussed in a previous column.)

When R is equal to X^, we find that
exactly 1/V?or 70.7% of the input volt¬
age appears across the output. And be¬
cause power is proportional to the
square of the voltage, half of the input
power is available at the output. This is
why the frequency at which Xq equals R
is called the half-power point. Also, a
50% drop in power is 3 dB below the
original level, so this frequency is also
called the half-power point. (Don’t con¬
fuse this with a half -voltage point, where
a 50% decrease in volts is -6 dB.)

You might think that 50% of the volt¬
age appears across the capacitor, and
the other 50% appears across the resis¬
tor. Such a response is correct if you are
talking about a purely resistive voltage
divider. But here, reactance is involved,
complicating the situation. Without going
into a detailed analysis, we’ll simply say

Fig. 3. Universal
frequency-response
curve for anRC
low-pass filter .

FREQUENCY-Hz

POPULAR ELECTRONICS

The better the training and equipment
the better you’ll be equipped.

Send for one of these FREE Illustrated Career Guides:

GFTMGtl V _

OPfliEni (■

CaiDr i v 'Ik
ns

Build and keep some of the finest technical equipment
made when you train with an NTS Project-Method home
study course. And jt’s usually the same type of equip¬
ment you’ll meet in the field and use on the job. It will
help you acquire first-hand experience and skill — help
prepare you better for a variety of exciting technical
careers:

ELECTRONICS DIVISION: Courses include professional
equipment like 5" solid-state oscilloscope, transistor
and tube-tester, vector monitor scope, 74 sq. in. B&W
TV, and solid-state stereo AM-FM multiplex receiver,
speakers. Color TV courses feature advanced NTS/
HEATH DIGITAL GR-2000 Color TV with silent varactor
diode tuning; digital read-out channel selection (with
optional digital clock), big 315 sq. in. screen.

MECHANICS DIVISION: Learn engine diagnostics, mo¬
tor overhaul, transmissions, automotive maintenance.
Courses include 9 in. solid-state automotive oscillo¬
scope, testers, tools, mechanic’s steel tool box, & more.

AIR CONDITIONING, REFRIGERATION/HEATING DIVI¬
SION: Learn servicing of commercial, industrial and
residential heating and cooling equipment. Courses in¬
clude hermetic unit analyzer, leak detector, charging
testing-purging manifold set, tools and more.

HOME APPLIANCES DIVISION: Courses cover repair
and maintenance of washers, dryers, ranges, smaller
appliances. Equipment includes NTS Circuit-Trainer and
professional multimeter.

LOWER TUITION FOR YOU: We employ no salesmen,
pay no commissions. You receive all home-study infor¬
mation by mail only. Make your own decision, your own
comparisons. Send card today or write for illustrated
catalog in field of your choice, all details.

NO OBLIGATION. NO SALESMAN WILL CALL

APPROVED FOR VETERAN TRAINING

Get facts on new 2-year extension.

NATIONAL*™!*) SCHOOLS

TECHNICAL-TRADE TRAINING SINCE 1905
Resident and Home-Study Schools
4000 So. Figueroa St., Los Angeles, Calif. 90037

NATIONAL TECHNICAL SCHOOLS

4000 South Figueroa St., Los Angeles, Calif. 90037

Please send FREE Color Catalog and Sample Lesson.
NO OBLIGATION. NO SALESMAN WILL CALL.

Dept. 205-126

G Electronics Division

□ Mechanics Division

□ Air Conditioning/Refrigeration/Heating Division

□ Home Appliances Division

NAME-

-AGE-

ADDRESS^

CITY_

Please fill in Zip Code for fast service.

_STATE_

□ Check if interested in G.l. Bill information.

□ Check if interested ONLY in classroom training in Los Angeles.

DECEMBER 1976

THE ANTI-THEFT BB ANTENNA LOOK

Til

PROTECT YOUR ANTENNA

lenno-loc il

really positive protection
designed to keep
, ^ your antenna intact and in
place — year round! Yes,
you may remove it for car
-^wash or long term storage
but them’s no need to.

; - every time you. park! 1

' It works like a charm in ML
all kinds of leather and \jj
keeps on working for

a years, tenno-loi

features a;4.u rn- proof
locking stud integrated
into a specially notched A
U-bolt with a S-iumbteR, k,
"JM corrosion proof m*

key lock. We also give Jfl
you a heavy-duty jfl
mounting bracketJ

and an electro-polished,
stainless steel replacement
cup, where needed, for easy,
quick installation. At S1 1 .95
(approx), it's a steal!

Get one today
■ Choice of
models> 10 f,t

| a Installs quickly, eas
'jjs your antenna secure,
irome plated, 5-tumbler
oston proof key lock,
^elusive, turn- proof,
bolt with lock-in stud.

I Made In U.S.A.;
patent pending.

lee Your Dealer i

A product of:.

VERN

CONSUMER F
Lake Succes*

low-pass filter shown in Fig. 1 is -6 dB
per octave (from a given frequency fi to
2 fi) and -20 dB per decade (from fi to

10fi).

This frequency response curve can be
approximated by two straight lines, as
the dashed region indicates. We can
therefore generalize the frequency re¬
sponse by saying that, from dc up to fc,
there is no attenuation of the input sig¬
nal. At this point, the response “breaks”
or “corners,” then falls at a rate of -6 dB
per octave.

Low-Pass Scratch Filter. Now let’s
look at a practical application of the RC
low-pass filter. Many old-time music
buffs treasure vintage 78 rpm records,
and learn to live with the high surface
noise that has developed on them over
the years. Most of this noise is com¬
posed of high frequencies. So if a low-
pass filter is inserted between, say, the
preamplifier and the power amp, and if a
proper cut-off frequency is chosen,
much of the noise can be filtered out
without sacrificing too much of the musi¬
cal content.

A cut-off frequency of 8000 Hz is a
fairly good choice. This corresponds to
an RC time constant of 20 mi¬
croseconds. Any reasonable combina¬
tion of a resistor and capacitor that will
give this result is satisfactory. For exam¬
ple, an R of 20,000 ohms and a C of
0.01 microfarads will yield the desired
response. By using the universal curve
shown in Fig. 3, with 1/(2itRC) equal to
8000 Hz, you can observe how the
high-frequency material will be filtered
out.

High-Pass Rumble Filter. So far,
we’ve considered low-pass filters which
pass, unhindered, signals below fc, and
increasingly attenuate signals above fc
as the frequencies rise. However, we
can make a high-pass filter which be¬
haves in exactly the opposite manner by
interchanging the positions of R and C
as shown in Fig. 4. It has a frequency re¬
sponse that is a mirror image or con¬
verse of Fig. 3. Accordingly, all frequen¬
cies above the cut-off frequency — still

° - Ik — f — °

o— -

Fig. 4. A simple RC
high-pass filter.

POPULAR ELECTRONICS

vOUT

that, where a resistance and a reac¬
tance are found, we must treat the volt¬
age across each of them as vectors . As
shown in Fig. 2, Vr and Vc are at right
angles to each other. Each has a magni¬
tude of 0.707, referenced to an input
voltage of 1.0. By simple trigonometry
(c2 = a2 + b2) V|n equals 1.0, which
agrees with our basic supposition. And
the phase angle — that is, the angle be¬
tween the Vim vector and the Vc vec¬
tor— is 45°.

The relationship between cut-off fre¬
quency fc and the values of R and C can
be summarized by the simple equation

fc = 1/(2ttRC) or 1/2ttT), where T is the
RC time constant in seconds. This fre¬
quency occupies an important point on
the RC low-pass filter frequency re¬
sponse curve shown in Fig. 3. In this
graph, the vertical axis represents the
fraction of the input voltage appearing at
the’ output of Fig. 1 . Also given on the
vertical axis is the decibel relationship
between VjN and V0ut- The horizontal
axis is the signal frequency on a loga¬
rithmic scale. This is done so that the
failing response characteristic quickly
approaches a straight line with a con¬
stant slope. The slope for the simple

it Neck, N Y. 1 1 021 (51 6) 487-01 40

CIRCLE NO. 68 ON FREE INFORMATION CARD

+ 9V

Fig . 5 . A 555 RC relaxation
oscillator that flashes LED’s.

determined by the formula fc = 1/
(2ttRC) — are passed unattenuated. Be¬
low this frequency, the circuit’s response
falls off at a rate of -6 dB per octave.

Here’s a practical application. Sup¬
pose your stereo system is troubled by
acoustic feedback or rumble. By insert¬
ing a high-pass filter with a suitable fc
between the preamp and power amp,
we can prevent these low frequencies
from reaching the speaker. The cut-off
frequency should be selected so that it
will cause no loss in bass response, but
do an effective job of attenuating the
rumble. A good choice is 16 Hz, corre¬
sponding to an RC time constant of
10,000 microseconds. With an R of
20,000 ohms and a C of 0.5 jaF, the de¬
sired response will be achieved.

If we wanted to go to a higher fc, say,
one octave up to 32 Hz, we need only
modify the RC product so that it is
halved. This could be done by using a
10,000-ohm resistor and a 0.5-p,F capa¬
citor, a 20,000-ohm resistor and a
0.25-p.F capacitor, or any other reason¬
able RC combination.

Timers and Oscillators. Last
month, we looked at two RC oscillators.
One was a neon-lamp relaxation oscilla¬
tor and the other used a 741 op amp as
a square-wave generator. The RC time
constant appears in the general formula
for the oscillating frequency of these re¬
laxation oscillators: fo = k/2 tt RC. The
value of the constant k depends on
whatever parallel resistance paths ap¬
pear in the circuit, and also on the power
supply used.

One very common application for the
RC combination is as a controlling ele¬
ment in 555 timer and oscillator circuits.
This versatile 1C can function as a
monostable or astable multivibrator. In
the first case, it will generate a single
pulse whose width is determined by the
RC time constant. In the second, two re¬
sistors and a capacitor determine the
amount of time the output is high, how

DECEMBER 1976

long it is low, the rate of repetition (fre¬
quency), and the duty cycle of the output
waveform. The circuits will work with any
supply between 5 and 1 5 volts, and the
pulse width or frequency is independent
of the value of the supply voltage.

The astable multivibrator shown in
Fig. 5 will produce square waves with a
period T equal to 0.693 (RA + 2 RB)C.
The output frequency will be the recipro¬
cal of the period (f = 1/T). And the duty
cycle, which is the portion of the time the
output is high, divided by the entire peri¬
od, is given by the expression D = RB
/(Ra + 2Rb). For the values shown in

Fig. 5, T is 0.525 seconds, f is 1.9 Hz,
and the duty cycle is 331/3%. This can be
verified by watching the LED’s flash.
When the output is low, the 1C sinks cur¬
rent for LED1 , a green light-emitting di¬
ode. When the output is high, there is no
voltage drop across LED1 , and it is dark;
but the 1C sources current for the red
LED2. Component tolerances will have
some effect on the nominal frequency.
However, if a tantalum capacitor is used
for C, it should be close to 2 Hz. Of
course, you can slow down the flash rate
by increasing the values of the resis¬
tances or capacitance. O

THE BEST EQ KIT VALUE ANYWHERE!

A Quiet* Announcement, Based On The Undistorted* Truth About Equalizers

Does the equalizer you're considering offer full ten band control with sym¬
metrical "mirror-image" boost and cut responses centered on ISO prefer¬
red octave bands? Does it have permanently-lubricated 60mm metai-cased
sliders with metal shafts and center click detents? Do the specs tell you
what to expect at all settings.. .or only at the "flat" setting, where the cri¬
tical tuned networks are bypassed? Does it employ advanced hum & satur¬
ation-free "gyrator" simulated inductors on all low and mid-frequency
bands? How about truly differential balanced and unbalanced inputs and
outputs for use in any audio system, amateur or pro? And "fit anywhere"
packaging designed for 19" rack, in-wall, in-console or optional wood cab¬
inet mounting? What about truly flat response (both amplitude and
phase angle) at the center reference setting?

WE BELIEVE IN OUR PRODUCTS. We want you to see them. ..read our fully-
illustrated assembly and applications guide. ..inspect the quality of the components...
at no risk to you! Simply use the coupon below to indicate the item(s) you want,
your name and address and enclose a check or money order (no COD or bankcards)
for the full amount. Upon receipt of your completed order, we'll rush your kit(s)
to you, pre-paid shipping in the U.S.A.

After careful inspection of the kit(s), you may return any or all items in their origi¬
nal unassembled condition for a full immediate refund if you are not totally satis¬
fied... (no questions asked.) And, if you decide to keep and build the kit(s), our
normal guarantee on the specs and parts still applies... if your properly assembled
kit(s) fail to operate as stated, we will exchange any defective parts free for the
first 30 days.

*QUIET 90dB below 1 volt input, 20 to 20K, set flat or fully boosted *UNDISTOR-
TED... Below 0.1%THD & 0.05%IM at any EQ setting,..below 0.05%THD and
0.0075%IM set flat. ORDER BLANK

QUAN. ITEM DESCRIPTION PRICE

( ) EQ-10M Single EQ module kit (mono) less power supply $56.00

( ) EQ-10SP Two EQ module kits (stereo) plus PS-4 power supply kit $130.00

( ) EQ-10QP Four EQ module kits (quad) plus PS-4 power supply kit $235.00

( ) EQ-1082P Eight EQ module kits plus two PS-4 power supply kits $460.00

( ) PS-4 Power supply kit(open frame)power up to four modules $ 20.00

( ) EQ-10WC Walnut veneer (genuine wood) cabinet fits EQ-10SP kit $20.00

NAME _

ADDRESS _

CITY _ STATE

ZIP _ COUNTRY

AMOUNT ENCLOSED $

Washington State residents add 5% state sales tax.
Returns of unassembled kits for refund must be made
within 10 days of receipt and returned items must
be packed in original condition, using original pack-
ing materials. Prices and "trial offer" valid for orders
postmarked on or before January 31, 1977. Outside
U.S. check reader service card for ordering
information. _ _ _

Delta-Graph Electronics Company

P.O. Box 741 Dept. PE Pasco, WA 99301

CIRCLE NO. 22 ON FREE INFORMATION CARD

Solid State

By Lou Garner

’TIS THE SEASON TO BE SOLID

THERE was a time — not too long ago — when choosing sol¬
id-state gifts for the holidays was a really tough task.
Prices were high and selections limited. Today, the job is
more of a cinch than a chore ... so much so, in fact, that
unless your shopping list is a short one restricted to such
items as diamond rings, fur coats, and caviar, chances are
you’ll find it next to impossible not to include at least one or
two solid-state items.

You can spend as much or as little as you’d like because
solid-state gifts are available at prices ranging from less than
five to as high as several thousand dollars.

For many, AM, FM, and combination AM/FM or multiband
radio receivers are excellent gifts, as aie portable tape record¬
ers. A screw-in solid-state dimmer for table lamps is a nice,
but inexpensive, gift for students, office workers and house¬
wives. If your budget permits, you’ll find that virtually everyone
will be delighted with a solid-state portable TV set (even more
than delighted if it’s a color model).

You might even consider giving a digital calculator to every¬
one on your list, selecting types and models appropriate to
each one’s age and interests. If you have a limited budget,
you’ll find simple four-function (often called “four-banger”)
models for less than ten dollars. On the other hand, if money
is the least of your problems! you can spend hundreds of dol¬
lars and thrill your friends with magnetic card programmable
calculators such as Hewlett-Packard’s HP-67 or Texas Instru¬
ment’s SR-52. Both firms can supply pre-programmed card li¬
braries for their instruments covering virtually every field from
finance to engineering. Tl also offers an optional thermal print¬
er accessory which delivers permanent copies of calculations,
including all program steps. Between these two extremes,
you’ll find moderately priced specialized instruments suitable
for students, scientists, engineers, accountants, salesper¬
sons, mathematicians, and retailers. And there are ultra-thin
models which may be carried in a purse or shirt pocket, mod¬
els with non-volatile memories for retaining bank balances,
folding models, and metric converters which housewives
should find handy as the metric system comes into broader
use. There are even special easy-to-use calculators for
youngsters, such asTI’s “Little Professor" and National Semi¬
conductor’s “QuizKid” models.

In one sense, the solid-state equivalent of such teaching
aids as flash cards, the educational calculators add new inter¬
est and excitement to the learning experience. For family fun,
there are calculator board games, such as Tl’s “Calculator
Squares” and “Check Out.”

A TV game attachment also makes a fine family gift. Elec¬
tronic tennis, anyone? These are covered in a separate article
in this issue.

Digital electronic watches make excellent gifts and are
available at prices to suit virtually every budget. If your wallet

is thin, but you have a special someone who would like a
watch, Tl offers several models in their TI-501 and TI-502 se¬
ries which list for less than twenty dollars each. On the other
hand, if you’re a lavish giver and have a bank account to
match, you might consider the ultra-limited-edition Pulsar
Time Computer® manufactured by Time Computer, Inc. (Lan¬
caster, PA 17604). Priced at a little under four thousand dol¬
lars (each, that is), this beauty combines a 6-digit, 5-function
(with memory) calculator and a 5-function digital LED wrist-
watch in a single 18-kt gold case with matching 18-kt gold
bracelet. It comes complete with a combination pen and key
presser tool. A less expensive version is available in stainless
steel for economy-minded individuals who must limit their gifts
to under six hundred dollars.

CB radio is big — and growing bigger every day. Spiced with
colorful language, it is considered as a hobby by many, as a
cult by some, and as a necessity by others. If your gift choice
is CB equipment, you can select a low-cost hand-held “walk¬
ie-talkie” (but not the 100 mw or less type that’s being phased
out) or spend hundreds for a complete mobile or base station.
New twenty-three-channel units are available at bargain-
basement prices right now because people foolishly think that
they’ll be obsoleted by the introduction of 40-channel types
next year. (They won’t!). Check the Popular Electronics
Citizens Band Handbook 1976 for help in making your
choice.)

For technically oriented friends who share your hobby inter¬
ests, you might select such gifts as project kits, special-pur¬
pose IC’s, circuit etching, breadboard kits, solder irons, or a
subscription to your favorite electronics magazine (plug). Try
to choose items which parallel your friends’ special areas of
interest — a microprocessor or memory 1C for those interested
in microcomputers or control circuitry, for example. Perhaps
you might choose a set of Tl’s new video game IC’s for those
with more general interests. The new Tl IC’s include the SN
76423 game logic with automatic random English, the
SN76425 horizontal and vertical sync generator, the
SN76426 character generator, the SN76427 wall and ball
generator, the SN76428 game logic with manual English, and
the SN76460 0 to W (Win) at 20 Digital Scoring. Supplied in
standard 300-mil wide plastic packages, these new IC’s may
be combined to allow games with multiple balls, multiple
walls, multiple players, and obstacles, and are suitable for use
in tennis, hockey, racing, battle, pool, and pin ball video
game’s.

If you prefer to choose more general technical gifts, you
might check into the latest offerings from the Vector Electron¬
ics Co., Inc. (12460 Gladstone Ave., Sylmar, CA 91342).
These include two new etched circuit board kits, Models
32X-1 and 32XA-1, and the Model 41 X modular breadboard
kit. The etched circuit kits feature positive-resist coated circuit

POPULAR ELECTRONICS

boards as well as bare copper clad boards, together with all
the materials needed for fabricating circuits using either the
direct-art-then-etch process or the positive photo-resist tech¬
nique. The more complete 32XA-1 kit includes seven circuit
boards and is priced at $28.00, while the smaller 32X-1 kit in¬
cludes two boards and costs $1 1 .50. Vector’s new 41 X bread¬
board kit features the firm’s patented slit-N-wrap wiring tool,
and includes ten 16-pin DIP sockets, press-in wrap posts plus
an installation tool, bus strips, socket cards, and other hard¬
ware, and is priced at a little over sixty-three dollars.

Clocking Your Circuits. Many digital logic and micro¬
processor circuit designs require a fixed frequency pulse
source for timing. The circuits supplying these signals, essen¬
tially simple oscillators, generally are called clocks, since their
primary function is to provide a timing signal. A number of sim-

1.6 nF (1.5 nF parallel with 0.1 nF)

^ext Rext Re,T

pie and inexpensive clock generator circuits are illustrated in
Figs. 1 through 3. Designed specifically for use with the Sig-
netics 2650 Microprocessor, the circuits are suitable for use
with any microprocessor or logic circuit requiring single¬
phase, TTL-level signals. They may be used, too, as general-
purpose signal sources for various other projects, such as sig¬
nal generators, electronic musical instruments, function gen¬
erators, or signal injectors if their operating frequencies are
changed to meet the needs of the specific application. All of
the circuits were abstracted from Application Memo MP52,
published by the Signetics Corporation (811 East Arques
Ave., Sunnyvale, CA 94086).

A pair of simple RC oscillators is shown in Fig. 1 . The first,
Fig 1 A, uses three standard 7400 inverters. Resistor R biases
the first inverter into its linear region while capacitor C pro-

Fig. 2. LC clock circuit

vides the feedback signal from the second stage needed to
start and sustain oscillation. The third inverter serves as a
simple buffer/driver. The circuit’s oscillation period is approxi¬
mately 3RC or, with the component values specified, about 1
jis, resulting in an output frequency of 1 MHz. In test mea-

...for a 10-5
from the
BLACK CAT

Whether you’re rolling in a convoy or
copying the mail from your home twenty,
you get a four roger every time with Black
Cat® CB accessories from Wawasee
Electronics. So if you’ve got your ears up
copy the following list of rugged
accessories:

• Antenna Whip

• JB 700 Mobile Antennas

• Trunk Lid Antenna Mount

• West Coast Antenna Mount

• 3-Ft. Jumper Cable

• 20-Ft. Jumper Cable

• Co-Phase Harness

• JB 1000 Dummy Load

• JB 1000 SM Oscilloscope / RF
Wattmeter / SWR Bridge

• JB 2000 SW Power Meter /SWR
Bridge

For a complete listing of all Black
Cat® CB accessories and dealers,
drop us a line and we’ll get right back
to you.

WAWASEE
ELECTRONICS

“HOME OF BLACK CAT® PRODUCTS”
Wawasee Electronics Co., Inc.

P.O. Box 36 • Syracuse, Indiana 46567
Phone: (219) 457-3191

DECEMBER 1976

CIRCLE NO. 70 ON FREE INFORMATION CARD

surements with a breadboarded circuit, the output signal had
a 10-ns rise time and a 7-ns fall time. While the circuit is rea¬
sonably stable, its output frequency will vary with changes in
both temperature and dc source voltage (Vcc)-

In a typical circuit, the output frequency dropped from
1043.20 kHz at 0°C to 990.45 kHz at 70°c with VCc held con¬
stant at 5.0 volts. When the temperature was held constant at
25°C, the output frequency dropped from 1028.95 kHz with a
4.75-volt source to 1013.63 kHz with a 5.25-volt Vcc- The
second RC oscillator, Fig. IB, uses a type N74123 monosta¬
ble multivibrator and is somewhat more stable with respect to
temperature variations than the inverter circuit. Here, the fre-

1.025 MHz Crystal

— IU

1 —

— t>°~

— 1>°-

- -

n n

—

I /40A

not k
OUTPMI
• t i nn mhi

Fig. 3 . Crystal clock circuits.

quency of oscillation is determined by the relative pulse width
of each monostable circuit and hence by the external R and C
values. Again, with the values indicated, the operating fre¬
quency is approximately 1MHz. As in the first circuit, the out¬
put frequency drops slightly with increasing temperature and/
or dc supply voltage.

Having even greater stability with respect to temperature
and voltage variations than the two RC oscillators, the LC

clock generator circuit shown in Fig. 2 uses a pair of 7400 type
inverters, an 82-ohm feedback resistor which also biases the
first inverter into its linear region, and a simple LC resonant
circuit made up of inductance L and capacitors Cl and C2. In
operation, the LC circuit forms a basic Colpitts oscillator in
conjunction with the first inverter, while the second inverter
acts as a buffer amplifier to minimize oscillator loading. The
operating frequency is determined by the L, Cl and C2 val¬
ues, and can be calculated using the following equation:

fosc — - - - -

2t vTc .

where “C" is the effective series capacity of Cl and C2,
or . . .

C=C1C2/C1 +C2.

With the values specified, the fosc as in the previous circuits, is
approximately 1 MHz. In experimental tests, the actual output
frequency of a breadboarded circuit varied from 1017.75 kHz
to 1 01 6.30 kHz as the dc source voltage was raised from 4.75
to 5.25 volts at 25°C. When the dc voltage was held constant
at 5 volts, the output frequency dropped from 1026.62 kHz to
1004.1 1 kHz as the ambient temperature was raised from 0°C
to 70°C.

In applications where maximum frequency stability is re¬
quired, crystal-controlled clock circuits should be used. A pair
of suitable circuits is given.in Fig. 3. The first, Fig. 3A, employs
two inverters in a crystal stabilized cross-coupled multivibra¬
tor. In operation, the 820-ohm resistors bias each inverter into
its linear region, while cross-coupling is provided by the crys¬
tal and by a 10-nF capacitor. A third inverter serves as a
waveform squarer and output buffer. All three are type 7404
(i.e., half of a hex inverter 1C). The circuit’s output frequency is
determined by the crystal and a suitable type must be used to
obtain a 1-MHz output signal. The second circuit, Fig. 3B, em¬
ploys an inexpensive 4.43361 8-MHz crystal of the type used
in many European color-TV sets. Again, the crystal is used
with cross-coupled inverters to form an oscillator; but, in this
case, the oscillator’s output frequency is divided by four by the
cascaded N7474 flip-flops to develop an (approximate) 1-

Fig. 4. Schematic diagram
for an electronic lock.

DECEMBER 1976

WORLD’S MOST PRACTICAL SOLDER HANOLINQ TOOLS

MHz output signal. In both circuits, overall frequency stability
with respect to temperature and source voltage is determined
by the crystals* characteristics.

When duplicating the clock generator circuits for specific
projects, remember that the series 7400 IC’s specified require
a well-filtered, reasonably well-regulated 5-volt dc source, and
that the power (Vcc) and GND connections must be made to
the specified pins of each device, as indicated by the appro¬
priate terminal diagrams. All resistors are Vx- or V^-watt types,
while the capacitors can be either ceramic, mica, or plastic
film units. Neither lead dress nor layout should be overly criti¬
cal but, of course, good wiring practice should be observed,
with signal-carrying leads kept short and direct.

Reader’s Circuit. Submitted by a 17-year old reader, Da¬
vid Wang (1490 Waukazoo Drive, Holland, Ml 49423), the di¬
gital electronic lock circuit illustrated in Fig. 4 features inex¬
pensive 7400 series TTL IC’s in conjunction with a pair of type
555 timers. David writes that he assembled his original model
for under five dollars by using an inexpensive surplus “4-
banger” calculator keyboard for his basic switch array. In op¬
eration, the lock is opened (i.e., the external sensitive relay is
activated) when a five-number combination is entered within a
specified time limit. No number may be entered twice or out of
sequence. If any number not in the combination is entered, a
“penalty” delay is activated which prevents circuit operation
for, during the penalty period, the lock circuit is held in reset
and not even the right sequence will activate it. The combina¬
tion of a limited operational time once the initial key is pressed
and an unknown penalty time if a wrong key is pressed makes
the lock exceedingly difficult to defeat by “guess” and mani¬
pulation.

The basic circuit consists of four interconnected J-K flip-
flips, with the Q terminal of the last one providing the circuit's
output signal. Operation is initiated when the 555 “enable”
timer is switched to a low state by depressing key 1 . Thereaf¬
ter, the flip-flips are clocked in turn by depressing keys 2, 3, 4
and 5 in order. After the preset time delay, the enable timer
goes to a high state, triggering the flip-flop chain and providing
an output signal. If any of the penalty keys is pressed acciden¬
tally, the penalty timer is activated, applying a signal through
logic gates to hold the flip-flops in a reset state for a given
time.

The initial (operational) time delay is established at about 3
seconds by a 1 -megohm resistor in conjunction with the 1-p.F
capacitor, R4 and C3, respectively, while the longer “penalty”
delay is determined by R5 and C4. Capacitor Cl, shunted by
R1, serves to reset the final flip-flop when the circuit is first
switched on. In the power supply circuit, R3 and C2 form a
simple keyboard debounce filter. Series resistor R2 in the pe¬
nalty timer circuit serves to stabilize the 555 against false trig¬
gering.

With neither parts placement nor wiring arrangement criti¬
cal, the electronic lock circuit can be assembled on perf board
using point-to-point wiring or on a suitable etched circuit
board, as preferred. All the resistors are !4-watt types, while
the capacitors can be either low-voltage ceramics or elec-
trolytics, as appropriate to their values. The flip-flop IC’s are
type 7473, the logic gates type 7400, and the timers, as in¬
dicated previously, type 555. The combination switches are
spst momentary-contact pushbutton types (as on a calculator
keyboard), while the main power switch is a spst toggle, slide,
or rotary type. The lock circuit’s output can be used to activate
a sensitive relay or as a control signal for other logic circuitry.

Until next year . . . Happy Holidays! O

POPULAR ELECTRONICS

SOLDERING +

DESOLDERING +

RESOLDERING =

SOLDER

AMHji

ELEMENTARY TO ELITE

©SPECIALLY4

designed

FOR

3§§

ADJUSTABLE
VACUUM STROKE

US140'

DESOLDERING TOOL

Compact tool for convenient tool
box storage. Precision molded
plastic barrel and low-mass
plunger creates rapid vacuum
impulse with negligible recoil.
Three position plunger adjusts
loading span to fit large or small
hands. Ample vacuum for most
circuit board desoldering require¬
ments.

^►distributor ►as?*

Coverall by U.S.and Foreign Patents and Pending Applications

►SYW®

15*51 ARMINTA ST., VAN NITYS. CALIF. STMS
24HR. PHONES LocaI (213)»l»-?334 L, A. (213)173*5
CABLE: ED3VNEX VAN TELEX 6S-1UI

144 PAGE TRAINING MANUAL

NCWf ,ooc

* ILLUSTRATIONS

CIRCLE NO. 28 ON FREE INFORMATION CARD

1702A MANUAL EPROM PROGRAMMER

Features hex keypad, two
digit hex address and two
digit hex data display. Con¬
trols include load, clear, go!

(step), key/copy, data in/
data out, and counter up/
down. Profile card includes
high voltage pulse regulator,
timing, 8 bit address and 8
bit data drivers/receivers. Two 6V2" x 9" stacked cards with
spacers. Allows programming in 20 minutes — copying in
5 minutes. Requires +5, —9, and +80 volts.

ASSEMBLED . $299.95

KIT . $189.95

NOW

The best of two worlds. . . use our 1702 EPROM programmer
as a manual data/address entry programmer ... or connect it
to your processor.

IMSAI/ALTAIR computer interface (requires 3 output ports,

+1 input port) and software . $49.95

Briefcase unit with power supplies and interface connectors
(assembled and tested only) . $599.95

ANNOUNCING

Our NEW 16K Byte Pseudo-Static, IMSAI/ALTAIR compat¬
ible RAM. Single card slot. Uses less power than equivalent
low power RAM. All memory chips socketed. Uses all prime,
factory fresh ICs. High quality, two-sided, through-hole-
plated circuit board. Crystal controlled, totally invisible
refresh system requires NO software management. Just plug
it in and use like STATIC memory.

Complete kit . $349.95

Assembled, tested, and burned in . $549.95

ASSOCIATED ELECTRONICS

12444 Lambert Circle • Garden Grove, C A 92641
(714) 539-0735

CIRCLE NO. 11 ON FREE INFORMATION CARD

YOU
CAN BE
SURE

MORE TIMES IN
MORE CIRCUITS
WITH SENCORE
DIGITAL
MULTIMETERS

SENCORE

A NEW BREED OF DVM's
BACKED BY 25 YEARS OF
ALL AMERICAN CRAFTS¬
MANSHIP, WITH SIX EX¬
CLUSIVE FEATURES, SO
YOU CAN BE MORE SURE,

MORE OFTEN .

l AND ALL WITH HI & LO ,
i POWER OHMS FOR MEAS- '
fe URING ACCURATELY IN
m SOLID STATE CIRCUITS.

DVM35 $124

3 digit LED display,

1 % DC V accuracy,
battery or AC operated

BONE THIRD LESS CIRCUIT LOADING to make
you sure that you are affecting the circuit being
tested as little as possible for more accurate measure¬
ments. Sencore digitals are 15 megohm, others are
10 megohm.

IB1 2000 DCV range to make you sure that you can
measure TV boost volts, scope voltages, medical
equipment, etc. Other digitals stop at 1000 volts.
High voltage probe extends measuring capabilities to
50 KV.

E] PROTECTED INSIDE AND OUT so you can be

sure that your meter is working and not in the repair
shop. Drop it from 10 feet, apply 1000 volts over¬
load and even apply volts on ohms accidentally and
Sencore digitals keep right on working.

CB Scene

By Ray Newhall, KWI6010

More on Mobile Antennas . Dec. 94

Computer Bits (Ogdin)

Interrupts & Real-Time . Jan. 88

Games for Learning . May 97

Computer Bits (Marsh)

Computer Users Tape System .. . . . Mar. 88

Computer Bits (Chamberlin)

Computer Graphics . July 86

Computer Music . Sept. 1 1 6

Computer Music Part II . Oct. 88

Mass Storage Systems . Nov. 106

Computer Bits (Gray)

Books on Programming . Dec. 101

DX Listening (Hauser)

Shortwave News From All Over. . . . . Mar. 91

Frequency Measurements . . . May 82

Listening to the Relays . Sept. 1 09

Change in the Air . Nov. 96

Editorial (Salsberg)

Buzz Words & OEM Distributors . Jan. 4

Good News for Mail-Order Buyers . Feb. 4

New-Project Stumbling Blocks . Mar. 4

WARC-79 and Communications Hobbyists . Apr. 5

Project Kit Suppliers . May 4

The Second Golden Opportunity for CB . June 4

Who Killed TV Picture Quality? . July 4

Planting Electronics Hobby Seeds . Aug. 4

Consumer "Radiation" Protection . . . .Sept. 4

Solar Energy . Oct. 4

Majority Rules— The Bitter Pill . Nov. 4

Turning the Electronics Corner . . . Dec. 4

English-Language Shortwave Broadcasts (Wood)

March and April . Mar. 92

May thru August . . May 84

September and October . Sept. 1 12

November 1976 thru February 1977 . . Nov. 102

Experimenter's Corner (Mims)

Using an Optoisolator . Jan, 101

TTL Sequence Generator . Feb. 101

Percussion Instrument Synthesizer . . Mar. 100

Pulse Modulation and Phase-Locked Loops _ _ May 101

Applications for the TTL NAND Gate . June 1 02

The Avalanche Transistor . July 104

The 567 Tone Decoder . Aug. 91

The LM380 Power Amplifier . Sept. 1 21

High-Voltage DC/DC Converters . . . Oct. 107

The Silicon Solar Cell . Nov. 110

The Neon Glow Lamp . Dec. 1 1 1

laside Basic Electronics

Fixed and Variable Resistors . July 94

Inside Basic Electronics (Prensky)

Using Resistances . Sept. 1 05

Capacitors and RC Circuits . Oct. 94

Capacitors and RC Circuits, Part 2 . Dec. 86

Solid State (Garner)

Prophecies for Next Year . Jan. 79

A Dandy Circuit . . . Feb. 92

Opting for Op Amps . Mar. 80

A Versatile New 1C . Apr, 90

Out of Tune Correction . July 6

A Universal Light Emitting Diode . May 78

Programmable Schmitt Trigger . June 82

Build Your Own Sonar System . July 81

Simple Stopwatch Splits Seconds . Aug. 73

114

POPULAR ELECTRONICS

An 1C That Is Also Dandy . Sept. 92

Rara Avis . Nov. 89

T»s the Season to be Solid . Dec. 90

Stereo Scene (Salsberg)

Audio Potpourri _ Jan. 1 8

Stereo Scene (Hodges)

Looking to the Future . Feb. 22

Tone Controls, Plain and Fancy . Mar. 20

Hi-Fi Upgrading Tips . Apr. 24

The Worid of Sound Contracting . May 1 8

Dateline 1976 _ _ _ ....... _ _ _ June 20

Perfecting Phono . July 22

The Great Tube/Transistor Controversy . Aug. 14

Greetings From Nihon! . Sept. 14

Consumer Electronics Show— Summer 1976 . Oct. 30

Mods and Modifiers . Nov. 22

Evaluating Four-Channel . Dec. 24

Test Equipment Scene (Solomon)

Making Good Use of Noise . Jan. 83

Can Test Equipment Be Wrong? . Feb. 91

Using Your Oscilloscope . Mar. 83

FEATURES AND TUTORIALS

Active Filters, Understanding (Lancaster) . Dec. 69

Antenna Rotators, Buyer’s Guide to (Carrole) . Aug. 39

Audio Electronics Today, The State of

(Feldman) . Sept. 57

Audio "Room Expander", A New (Solomon) . May 55

CB Base Station Antennas, How to Choose

(McVeigh) . Apr. 50

CB Bicentennial Highway Buddies, Your

(Sweeney) . Apr. 59

CB Equipment Terms Made Easy for Buyers . Apr. 62

CB Radio Range, How to Predict (Gerson) . Dec. 48

CB Transceiver and Antenna Manufacturers . Apr. 64

Collecting Shortwave Folk Music (Stanbury) . May 39

Color TV Receivers, The New 1976 (Margolis) _ Feb. 41

Computer Codes, Introduction to (Robbins) . Apr. 46

Designing Optimum-Q and Small Inductors

(Martin) . . . Sept. 101

Digit Probe (Solomon) . Dec. 56

Diodes, What Do You Know About (Balin) . . Feb. 73

Dummy Antennas for Hams and CB’ers (Frye) . Feb. 65

DX Programs and DX Clubs on Shortwave (Wood) .. Aug. 53
Electrical Grounds for Electronic

Equipment (French) . May 47

Electronic Switching with Transmission

Gates (Pascoe) . Feb. 62

Envelope Generators & Sequencers for

Electronic Music (Lancaster) . Jan. 58

Find the Hidden Electronics Words (Sear) . Oct. 71

Fusing Quiz (Balin) . Sept. 32

Guide to Choosing TV & FM Antennas (Green) . July 61

"Home-Brew” Phono Preamp Design, Guide to

(Bohn) . Sept. 60

HP-45 Calculator As a Stopwatch or Elapsed-

Time Indicator, How to Use the (Miller) . June 67

1^ — A New Transistor Logic Family (Haffner) . Jan. 56

In’s and Out’s of Computers for Beginners

(Mitchell) . June 47

Install a CB Mobile Transceiver, It’s Easy

to (Davis) . Apr. 55

Lamp Circuit Quiz (Balin) . Dec. 99

Learning Electronic Theory with Hand

Calculators, Part I (Noll) . July 43

Out of Tune Correction . Sept. 6, Oct 8

Learning Electronic Theory with Hand

Calculators, Part II (Noll) . Aug. 58

Learning Electronic Theory with Hand

Calculators, Part III (Noll) . . Sept. 70

LED Bargraph Readouts (Mims) . Sept. 74

Microwave Ovens for the Home (Eva) . July 39

Minimize Scope/ Probe Combination Errors,

How to (Sear) . Mar. 54

Mobile Communications: CB Vs. 2-Meter FM

(Frye) . July 79

Multiplexed LED Displays Simplify Circuits,

How (Delaney) . Mar. 62

Out of Tune Correction . May 6

NiCd Batteries, The Care & Feeding of (Burr) . . Mar. 39

Peri Board Wiring Techniques for

Experimenters (Mangieri) . Apr. 66

"Photophone ", Talk Over a Sunbeam with (Mims) .... Feb. 54

Power Supply, Protecting Your (Arp) . Nov. 56

Professional Vs. Consumer Tape (Zide) . Nov. 66

Programmable Calculators, Here Are the New

(Mims) . May 29

Propagation Delay— The Logic Gremlin (Tenny) . Dec. 64

Propagation Forecasts for Radio

Communicators . Nov. 34

Radio Astronomy, An Introduction to

(Heiserman) . Jan. 41

Recording for Stereo with Four-Channel

Tape (Unkletter) . Sept. 64

Select a Hobbyist Microcomputer, Howto (Gray) _ Dec. 51

Tape Recorders, What’s New In (Feldman) . Oct. 45

Temporary Permit Form 555-B for CB Radio . July 98

Ten Speaker Enclosure Fallacies (Weems) . June 39

Tips on How to Choose Speaker Systems (Sisk) ..... Sept. 66
Tools for Electronics Experimenters (Mangieri) . Oct. 55

TV Electronic Games, Roundup of (Carrole) . Dec. 32

Universal Interface Between Low-Power Logic
and Load Drivers (Gregory) . June 94

PRODUCT TEST REPORTS

ADC Aocutrac 4000 Record Player . Oct. 72

Alpha Wire Model STRP-25 Wire Strippers . SepL 91

Bang & Olufsen Beogram Model 1900

Record Player . Aug. 68

B. I .C Model 980 Multiple Play Manual Record

Player . . . Jan. 68

B&K Precision Model 280 DMM . . . May 77

Browning Golden Eagle Mark III AM/SSB Base

Station . Feb. 82

Continental Specialties "Design Mates” . June 80

Craig Model 4104 Mobile AM CB Transceiver . June 78

Crown Model IC-150A Preamplifier . Sept. 82

Dual Deluxe Cassette Deck . Feb. 78

Dual Model 1249 Automatic Record Player . . Sept. 83

Epicure Model Four Preamplifier . May 74

Handic Model 2305 AM CB Transceiver . . . Sept. 84

Heathkit Model AN-201 6 "Modulus” Control
Center, Heathkit Models AA-1 505 and

AA-1506 “Modulus" Power Amplifiers . June 72

Heathkit Model GB-1201 Digital Stopwatch . Mar. 73

Heathkit Model TD-1006 4-Channel Color

Organ Kit . Jan. 74

Hewlett-Packard Model 3476A Automatic DMM . Apr. 88

Hickok Model 370 Analog Multimeter . July 77

Jensen Model OPC-21 Speaker System . Feb. 80

Jerrold Model TRC-1 2 VHF TV Remote Control

Accessory . Feb. 89

Kris Victor II AM Mobile CB Transceiver . May 76

Lafayette Corn-Phone Maik II AM CB Base

Station . Apr. 86

Luxman Model T-310 AM/Stereo FM Tuner . Apr. 76

Marantz Model 5220 Stereo Cassette Deck . Mar. 68

Micro-Acoustic Model 2002e Phono Cartridge . Oct. 74

Midland Model 1 3-882B Mobile AM CB

Transceiver . Mar. 72

MXR Stereo Graphic Equalizer . July 75

Nikko Model 7075 AM/Stereo FM Receiver . July 66

OAE Model OP-80A TTY Paper Tape Reader . Sept. 90

Onkyo Model TX220 AM/Stereo FM Receiver .......... Mar. 70

Onkyo Model TX-4500 AM/Stereo FM Receiver . Aug. 66

Pace Model 145 AM CB Transceiver . Oct. 82

Pickering Model PP-1 Phono Preamplifier . . Jan. 69

Pickering Model XV-15/625E Phono Cartridge . Nov. 79

Pioneer Model RG-1 Dynamic Processor . Apr. 80

Pioneer Model SF-850 Electronic Crossover . . July 74

Phase Linear Model 200 Basic Power Amplifier . Oct. 76

Processor Technology Model VDM-1 Video

Display Module . Oct. 84

Realistic Model TFtC-57 Navaho CB Transceiver . Aug. 70

SBE Model 12SM Opti/Scan Digital Scanning

Receiver . July 76

SBE Model 32CB Formula D Touch/Com CB

Transceiver . . . ....... _ _ Dec. 78

Schober Theatre Organ ... . Nov. 86

Sencore Model CR31 CRT Tester & Restorer . . Jan. 73

Sencore Mode! DVM32 Portable DMM . Aug. 72

Sencore Model TF70 Portable Transistor Tester . Dec. 79

Shure Model M24H All-Format Phono Cartridge . Dec. 76

Siltronix Mohawk AM CB Mobile Transceiver . Nov. 84

Sound Concepts Model SD-50 Delay Unit . June 76

Spectra Acoustics Model 210 Graphic

Equalizer . Nov. 78

Stax Model SR-5 Electrostatic Headphones . . May 73

Technics Model SA-5460 Stereo Receiver . . Dec. 74

Tram XL AM CB Transceiver . . Jan. 70

Triplett Mode! 60 Multimeter . Feb. 88

Tri-Star ‘Tiger SST' CD Ignition System . . Mar. 78

TEST EQUIPMENT AND TV
SERVICING

A/D Temperature Converter, An (Prudhomme) ........ Dec. 62

Audio Detective. Build the (Tenny) . May 41

Automatic Diode Checker (Stitt) . June 57

Capacitance Meter, Build this Low-Cost

(McGahee) . Oct. 64

Color TV Receivers, The New 1976 (Margolis) . . Feb. 41

Curve Tracer Checks Semiconductor Quality

(Lyle) . Mar. 58

Digit Probe (Solomon) . Dec. 56

High-Frequency Voltmeter, Build a $25 (Sear) .......... Jan. 46

1 -Hz to 1 -MHz Frequency Counter, Build a

Low-Cost (Huffnagle) . Aug. 48

"Junk-Box" 5-Volt Power Supply, A (Foss) . . May 66

Logic Probe, A Simple (Lefferts) . May 60

Measure the Sun's Energy with a Solar

Radiometer (Jochem) . Dec. 45

Minimize Scope/Probe Combination Errors,

How to (Sear) . Mar. 54

Temperature Meter, Build a Low-Cost (Russo) . Feb. 70

Update Your Multimeter with a CMOS Millivolter
(Dage) - July 47

Without our
software,
we’re just
another
flasher.

Let’s face it. No microcomputer is
worth a dime if you can’t make
it work. Even E&L’s Mini-Micro¬
designer would be just a “light
flasher” if it weren’t for our soft¬
ware system.

But the fact is that our tutorial soft¬
ware is the best in the business.
Not just a pathetic rehash of chip
manufacturers’ specifications. But
a clearly written, step-by-step in¬
struction that teaches you all about
the microcomputer. How to pro¬
gram it. How to interface it. How to
expand it.

The teaching material is written by
Rony/Larsen/Titus (authors of the
famous Bugbooks). It’s called Bug-
book V. And it teaches through ex¬
periments designed specifically to
get you up to speed on our Mini-
Microcomputer (MMD-1). And you
don’t need any prior knowledge of
digital electronics!

The best news? E&L’s MMD-1 costs
only $380 in kit form, including all
software and teaching material.
Send your check or Money Order
today (or complete BankAmeri-
card/Master Charge information).
We’ll pay shipping charges any¬
where in continental US.

[circuit DESIGN, INC.

* Division of E & L Instruments , PO. Box 24,
I Shelton, Conn. 06484

I believe you, I am ready to order at $380.00

for the MMD-1 Kit. Enclosed find my Check _

Money Order _ or charge information for

BankAmericard _ or Master Charge _

(Make sure you sign the order blank)

Name: _

Address:.
City: _

State:

_Zip Code:.

I Signature:.

_ :* :

Circuit Design will prepay shipping charges
anywhere in the US. Contact the factory for
additional charges elsewhere.

PS: If you want an assembled and tested
unit order the MMD-1 /A at $540.00.

115

DECEMBER 1976

ELECTRONICS MARKET PLACE

NON-DISPLAY CLASSIFIED: COMMERCIAL RATE: For firms or individuals offering commercial products or services, $2.25 per word (including name and
address). Minimum order $33.75. Payment must accompany copy except when ads are placed by accredited advertising agencies. Frequency discount; 5% for 6
months; 10% for 12 months paid in advance. READER RATE: For individuals with a personal item to buy or sell, $1.35 per word (including name and address.)
No minimum! Payment must accompany copy. DISPLAY CLASSIFIED: 1” by 1 column (2-1/4” wide), $260.00. 2” by 1 column, $520.00. 3” by 1 column, $780.00.
Advertiser to supply film positives. For frequency rates, please inquire.

GENERAL INFORMATION: First word in all ads set in caps at no extra charge. All copy subject to publisher’s approval. All advertisers using Post Office Boxes
in their addresses MUST supply publisher with permanent address and telephone number before ad can be run. Advertisements will not be published which
advertise or promote the use of devices for the surreptitious interception of communications. Ads are not acknowledged. They will appear in first issue to go to
press after closing date. Closing Date: 1st of the 2nd month preceding cover date (for example, March issue closes January 1st. Send order and remittance to
POPULAR ELECTRONICS, One Park Avenue, New York, New York 10016, Attention: Hal Cymes.

FOR SALE

FREE! Bargain Catalog— I.C.'s, LED’s, readouts, fiber
optics, calculators parts & kits, semiconductors, parts.
Poly Paks, Box 942PE, Lynnfield, Mass. 01940.
GOVERNMENT Surplus Receivers. Transmitters,
Snooperscopes, Radios, Parts, Picture Catalog 25 cents.

Meshna, Nahant, Mass. 01908. _

LOWEST Prices Electronic Parts. Confidential Catalog
Free. KNAPP, 3174 8th Aye. S.W., Largo, Fla. 33540.
ELECTRONIC PARTS, semiconductors, kits. FREE FLYER.
Urge catalog $1.00 deposit. BIGELOW ELECTRONICS,

Bfuffton, Ohio 45817. _

RADIO — T.V. Tubes — 36 cents each. Send for free catalog.
Cornell, 4213 University, San Diego, Calif. 92105.
AMATEUR SCIENTISTS, Electronics Experimenters,
Science Fair Students. , .Construction plans — Complete,
including drawings, schematics, parts list with prices and
sources. . .Robot Man — Psychedelic shows — Lasers —
Emotion /Lie Detector — Touch Tone Dial — Quadraphonic
Adapter — Transistorized Ignition — Burglar Alarm —
Sound Meter. 4. over 60 items. Send 50 cents coin (no
stamps) for complete catalog. Technical Writers Group,

Box 5994, University Station, Raleigh, N.C. 27607. _

METERS — Surplus, new, used, panel or portable. Send for
list. Hanchett, Box 5577, Riverside, CA 92507.

SOUND SYNTHESIZER KITS— Surf $12.95. Wind $12.95,
Wind Chimes $17.95, Electronic Songbird $6.95, Musical
Accessories, many more. Catalog free. PAIA Electronics.

Box J 14359, Oklahoma City, OK 73114. _

BUGGED??? New locator finds them fast. Write, Clifton,
11500-L N,W. 7th Avenue, Miami, Florida 33166.

YOU WILL SAVE BIG MONEY! Surplus, Clearouts,
Bankruptcy, Inventory, Deals. Catalog $1 (redeemable).
ETCOA Electronics, Box 741, Montreal, H3C 2V2. U.S.

Inquiries. _ _

HEAR POLICE/FIRE Dispatchers! Catalog shows
exclusive directories of ‘'confidential” channels, scanners.
Send postage stamp. Communications, Box 56-PE,

Commack, N.Y. 11725. _

SURPRISE! Build inexpensively, the most Unusual Test
Instruments, Futuristic Gadgets using Numerical
Readouts! Catalogue Free! GBS, Box 100A, Green Bank,

West Virginia 24944, _

TELEPHONES UNLIMITED, equipment, supplies. Catalog

50 cents. Box 1654E, Costa Mesa, Calif. 92626. _

UNSCRAMBLERS; Fits any scanner or monitor, easily ad¬
justs to all scrambled frequencies. Only 4” square $29.95,
fully guaranteed. Dealer inquiries welcomed. PDQ
Electronics, Box 841, North Little Rock, Arkansas 72115.
RECONDITIONED Test Equipment, $0.50 for catalog.
Walter's Test Equipment, 2697 Nickel, San Pablo, CA
94806.

TELETYPE EQUIPMENT for sale for beginners and exper¬
ienced computer enthusiast. Teletype machines, parts,
supplies. Catalogue $1.00 to; ATLANTIC SALES, 3730
Nautilus Ave., Brooklyn, NY 11224. Tel: (212) 372-0349.
JAPANESE TRANSISTORS, all transistors original factory
made. Free catalog. West Pacific Electronics, P.O. Box
3879, Torrance, CA 90510.

YOU WANT TO BUILD IT; WE WANT TO HELP. WE SELL
CONSTRUCTION PLANS with an Engineering Service.
TELEPHONE; Answering Machines, Speakerphones, Car-
phones, Phonevision, Touch Button Dialers. TELEVISION:
VTR, 1” Color TV Set, PONG, $25.00 Camera, COLOR
PROJECTION TV. HOBBYIST: Electron Microscope, $75
software programmable computer. BROADCAST; Special
Effects Generator, Chroma Key, Audio Board, DA's.
COURSES: Telephone Engineering $52.00, Detective
Electronics $29.50, 1C Engineering $65.00, PLUS MUCH
MORE. NEW Super Hobby Catalog PLUS year’s sub¬
scription to Electronic News Letter AIR MAILED $1.00. Don
Britton Enterprises, 6200 Wilshire Blvd., Los Angeles,

Calif. 90048. _

SEMICONDUCTOR AND PARTS Catalogue, $1.00 refund¬
able, from the semiconductor specialists. J & J Electron¬
ics, Box 1437P, Winnipeg, Manitoba, Canada. U.S.

Inquiries. _

ELECTRONIC ignition; Capacitor-Discharge, pointless.
Auburn Sparkplugs. Wheel Stabilizers. Information 20
cents. Anderson Engineering, Epsom, N.H. 03234.

MECHANICAL, ELECTRONIC devices catalog 10 cents.
Greatest Values — Lowest Prices. Fertik’s, 5249 MD”,
Philadelphia, Pa. 19120.

POLICE, Fire monitors, scanners, crystals, CB
Transceivers, New Crystal-less scanners. Discount priced.
Box 19224, Denver, CO 80219.

Same day shipment. First line parts only. Factory
tested. Guaranteed money back. Quality IC's and
other components at factory prices.

INTEGRATED CIRCUITS

P.O. Box 443QC Santa Clara, CA 95Q54
(408) 988-1640

7ioam

SM7400N 17

SN7402N 17

SH7404N 19

SN7410N 17

SN7414N 63

SN7417N 39

SN7420M 17

SN743M 20
SN7438N 25

SN744QN .17
SN7447N 60

5N7450N 17

SN7473N .36

SN7474N .32

8N7475N 49

SN74B3N .70
SN74B6N .39
SN7480N 2.00
SN7490N .45

SN749TN 45
SN7493N .49

SN74t00N 90
SN74107N .39

SN74121N .39

SN74145N 89

SN74150N 95

SN74151N .75
SN74154N 1.10
SN74157N 95

SN74161N .95

SN74I74N 1.19
SH74175N .90

SN74191N 1.25
SN74193N .85

SN74284N 6.00
SN74285N 6 00
SN74298N 165
T4LM0 TTl'
SN74LS00N .34
SN74L502N 34

SN741S04N ,39

SN74LS08N .39
SN74LS10N .39
SN74LS20N .34
SM74LS2SN .41
SH74LS30N .34
SN74LS3W .30
SN74LS74N .59
SN74LS7SN .75
SN74LS90N 1.10
SN74LS93N 1.10
SN74LS95N 1.89
SN74LS107N .52
SN74LS163N 2.05
5N74LS258N 2.20
UNUA

CA3082 1.90

CA3089 2.75

LM361AN .35
LM301AH .35
LM307N 35
IM3Q8N .69
LM309K ,95
LM311H .90
LM318 1.35

LM320K-S 1.35
LM3Q2K-1? 1.35

LU320K-15 1.35

LM320T-5 1.60

LM320T-B 1.60
LU320M2 1.60

LM320T-15 1.60

LM324N 1.10
IM339N 1.55
LM340K-5 1.60

LM340T-5 1.50

LM340T-8 1.70

LM340T-12 1.70

LM340T-1S 1.70

LM343H 4.25
LM358N 2.40

LM380N 100
LM703H 40
LM709H 26
LM723N .44
LM733N 89
IM741CH .35
LM741N .25
LM1303N .82

LM2902 2 20

IM3900N .55

LM3909N .89

MC145BV .59
N65401 3.90

NE550N .65
NH5S5V 43
N6556A 1.00

NE565A 1.00
NE566V 1.65
NE567V 1.25
5N754S1CN .39

SN75452CN .39

SN75491CN .50

SN75492CN .55

SN75494CN 89

A bo D CONVERTER
8700CN 16 00

CHOI

CD34001 Fin. .50
C04001 .25

1 35 74C160 2.00

2 00 74C192 2.40

.25 74C221 2.75

1.20 74C925 10 50

32 74C927 12.00

INTERFACE

ve/i

ELECTRONICS

OSOO20CN 5 MHz
Dial M0S dock
Drtwt 3.:

MM5371N 5.50 Drtrtr

MM 584 1 10.80 ii>at,acr

CT7001 5.80 UMT'HFC

MM5375AA/N 4.00 ST?, 013
MM5375AB/N 4.00
MAI 002 Compleie Uott
modul* minus irffmr ind
switches $9 95 JMS23

4 digit, 7 tuiKtlDfl flop- N 823 128

N62S23 3.25

NB2S123 4.00

NB2SI28 4.85

REHIT0M
tt m 5% In quinHUtt

2111*1 700

2112-2 7.90

IS13B 10.00

21L0S-T 2.50

8220 11.50

MM50S8 2.20
MMS060 3.20
MM52S2 .90
MM 5330 9.75

26 MM5311 3 60

28 MM5312 4.00

2 96 MM5313 3 60

.75 MM5314 3.90

2 10 MM5315 5.25

10wo*JP«oniy.$100 d 23 ptr lypi 03
ic sockets mtitau

SoMlr Tin Low Profllt 1 MHz
PIN 1 UP Pitt 1UP

8 15 24 .36 * “S

14 18 28 43 J MW

16 20 36 58 0 MHz

18 27 40 61

22 35 20 UHj

MICROPROCESSOR
8080 «rrlH drti 24 50 3Z™

8080A wtfi diU 33.50 MISCELLANEOUS
SPECIAL PRODUCTS 12 Vo« 300 mi

LM1B12N Ultrasonic Irmslotmer

TiiniuivM 7 SO K*m 8043

LM3909N LEO Fustier/ l(M

Oscillator 89 rns ■

LM379S Dwl BW _ M),.

Audio Amo lifter 5.00 OrmQe TD1B

7520 Claim photocells .25
MICROPROCESSOR HT
SJgnwIcs SK3000KTUW0A
S234 00 value Just *100 00
INCLUDES: 2-2K RAM
4-3002 3-82S1U

1-3001 2-8T26

1-74S182 1-8T31

6K o( PROM, no PC board
NATIONAL SC/MP KIT
Full Instruction manual plus board
and at components including
RAM and ROM *99.00
Data Ammi Amsgimirrl
Kit. Inslt. Ind 10,00

Encodar H0016&-5 7.50

Digital Alarm/Clock Kits

6-. 50 LED Displays.

Bat Kfy operated, beautiful finish. quarlz cryslal

vmmr. E^Ucnt for mo Ji:mp on mil ol any dual.
r-]r, [,[!. q\z year guaraniEe ^arJilidk fciy assembled)

fiVC-4 digitzJ dock Ur >jnd a\mm $36.95

HVC-EA djgdsl ttock la( with. gUxnn and radio or

Upt player UnnKup plus snooze ctfiDti 54.95

Mile Per Gallon Circuit

Digital Flow Sensor $29.50
Speed Transducer 8.00

(Specify car make and year)
CMOS Rate Multipliers 19.95
2-. 50 in. Displays 2.50

(orange or red)

Not a Cheap
Clock $17.45

includes everything
except case.

2-PC boards. 6-.50 LED
Displays. 5314 clock
chip transformer, all

Includes circuit description.

PC Board not included.

components and full
instructions.

60 Hz Crystal Time
Base Kit $5.95

Converts digital clocks from
AC line frequency to crystal time
base. Outstanding accuracy.
Kit includes: PC board,
MM5369, crystal, resistors,
capacitors and trimmer.

IC UPDATE
MASTER MANUAL

Complete IC data from
ail Manufacturers. 14,000
cross references. $30.00
with update service.

Limited quantities available.
Domestic Postage, add
$2.00, Foreign. $6.00

QUEST CATALOG.

OdlculjtlOf Module £2 .9 5

CnmcJcIc module minus

■:Lvlii:,ir:l £awe snd 1rjnsfo/TT>§r.

COSMAC ‘ELF

RCA Microcompuur CDP1822 $39 00
2ibz S -Go C0P1824 S 9 00
CDPiwk $29.50 COP1852 $10 25

CDP1821 $39 00 5082-7340 S 4 50

Cosmac users manual $7.50
Complete kit of additional parts
minus power supply and
board $40.00

DESCRAMBLERS: Several Professional Models that work
with all Scanners. Tone Encoders/Decoders, Scanmate,
AAPP, Radar Detectors, Big Ears, Alarms, Books, Kits,
parts. Catalog 25 cents; KRYSTAL KITS, Box 445, Benton-

vilte, Ark, 72712. _

CARBON FILM RESISTORS. Brand new as low as 1.7
cents. Discounts of 20%, Prompt delivery. FREE
samples/Specifications. COMPONENTS CENTER, Box

134P, N.Y., N.Y. 10038. _

WHOLESALE C.B., Scanners, Antennas, Catalog 25 cents.
Crystals: Special cut, $4.95, Monitor $3.95. Send make,
model, frequency. G. Enterprises, Box 461P, Clearfield, UT
84015.

Send for your •
information j
packet today-!

which also include* circuit •
function*, component line-up,*
and accessories. Information *
I — Packet $1.00 (refundable *

. with order). #

VISU lex P. o. Box 4204P Mountain View, CA 94040 •

COMPUTER HOBBYISTS! Bargain hunt and sell via
ON_LINE. 18 issues/Vear — $3.75. Free Sample. ONJJNE,
24695 Santa Cruz Hwy., Los Gatos, CA 95030.

PLANS — Video Pong, . .$2.00. Laser. . .$2.00. Projection
TV... $2.00. Catalog 50 cents. Technologic, Box 5262,

Orchard Lake, Michigan 48033. _

NEW ADJUSTABLE THREE OUTPUT REGULATED
POWER SUPPLY, plus 900 parts worth $400.00 list. Solid
state CARTRIVISION television recorder electronic unit.
Schematics, parts cross reference. HEATHKIT television
transistor substitutions. Power CB radios, MICRO¬
PROCESSORS. $17.95 plus $3.50 S&H, USA. Free
Brochure, Master Charge, BankAmericard. Satisfaction
guaranteed. MADISON ELECTRONICS COMPANY, IN¬
CORPORATED, Box 369, D55, Madison, Alabama 35750.

LOW cost digital/analog test equipment. Exceptional
values. Free catalog. Salen Electronics, Box 82, Skokie,
Illinois 60076.

DON’T LET VOLTAGE TRANSIENTS ZAP YOUR HI-FI.
Solid state equipment protector plugs into outlet protects
any transistorized equipment. $6.95. Kopp Electronics,
1650 William St., Buffalo, N.Y. 14206. Free Brochure.
LEARN Design Techniques. Electronics Design News¬
letter, Digital, linear construction projects, design theory
and procedures. Annual Subscription $6.00, sample copy
$1.00. Valley West, Box 2119-B, Sunnyvale, CA 94087.

116

CIRCLE NO. 53 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

DIGI-KEY CORPORATION

Quality Electronic Components
Double-Digit Discounts
Save You Even More

|I«U"

NATIONAL SEMICONDUCTOR CLOCK MODULES

MA1010A 12 Hour (AM-PM) Version .
/V MA1010C 24 Hour Version .

r /

MA1002A 12 Hour (AM-PM) Version . $10.50

MA1002C 24 Hour Version . $10.50

High LED Pjgjg

High LED Digit*

Special transformer and 6 switches,
when ordered with module add $3.45

Special transformer and 6 switches
when ordered with module add $3.45

Hobby-Wrap-30 $5.95

Strip*, Wraps bin) Unwrap* 30 go. wke on standard wiro wrapping pit

ACE201-K

$24.95

% MAT 002 & MAT OTO Series
~ Electronic Clock Modules

The MAI 002 & MA1010 Senes Electronic Clock Modules
ore assembled and pretested modules which combine a
monolithic MOS-LS! integrated clock circuit, 4-digit LEO
display, power supply and other associated discrete com¬
ponents on a single printed circuit board to form o complete
electronic clock movement. The user need odd only o trans¬
former and switches to construct a digrtol clock for applica¬
tion in dock-radios, olorm or instrument panel clocks. Time¬
keeping may be from 50 Of 60 Hz inputs and 12 or 24 hour
display formats may be chosen. Direct LED drive eliminates
RF interference. Time setting is mode easy through use of
"Fast" and "Slow'' seonning controls.

The MA1002A ond MA101QA hove o 12 hour display with an
AM and PM indicator. The MA1002C and MA1010C hove a
24 hour display.

Features include atom* "on" and "PM" indicators, "sleep"
ond "snooze" timers ond variable brightness control capa¬
bility, The modules are extremely compact, the MA1002
measuring 1.375" by 3.05", the MA1010 measuring 1.75"
by 3.75". This small size is ochieved by bonding the I.C.
to the bock of the circuit boord.

It is highly recommended that the transformer be obtained
with the clock module as H is a special dual secondary
type not otherwise readily available.

Double Digit Discounts Save You Even Morel

WIRE WRAPPING WIRE

1,032 SOLDERLESS PLUG-IN TIE POINTS
CAPACITY: I P TO 12 14-PIN DIP’*
TWO Sway binding posts
She. 4-9/16" by

Kit form •

■m?

INTEGRATED CIRCUITS - TTL, CMOS, LINEAR & MOS

WIRE WRAPPING WIRE IN BULK

Red or Bbck 30 go. Kynor

100* 52,00 500' SB. 50 1000* SI 5.00

I ENTIRE ROCKWELL CALCULATOR LINE
ON DISCOUNT IN OUR LATEST CATALOG

LM2111N 1.25

IM309K 1 .B0
LM324A 1.20
IM340T-5 1.25

IM340T-6 1.25

LM340T-8 1.25

LM340T-12 1.25
LM340T-15 1.25
LM340T-18 1.25
LM340T-24 1.25
LM3900N 38

LM3909N 39

MCI 456V 1.00

MCI 458V .53

MC33Q2P 1.15
NE536T 3.24
NE540L 2.04
NE555V .48
NE556A .88
NE560B 3.83
NE561B 3.83
NE562B 3.83
NE565A 1.25
NE566V 1.28
NE567V 1.36
UA709CV .44
UA710CA .44
UA711CA .53
UA723CA .60
UA733CA .75
UA741CV .44
UA747CA .70
UA748CV .49
uA7805CU 1.25
UA7806CU 1.25
UA7808CU 1.25
uA7812CU 1.25,
UA7815CU 1-25
uA7818CU 1,25
UA7024CU 1-25

SILICON TRANSISTORS

MPS918, MPS930, MPS2222A, MP52369A, MPS2712, MPS2907A, MPS3392.
MPS3393, MPS3394, MPS3395, MPS3563, MPS3565, MPS3638, MPS3638A,
MPS3640, MPS3641, MPS3643, MPS3645, MP53646, 2N3904, 2N3906, 2N4124,
2N4126, 2N4401, 2N4403 , 2N4410, PN4888, 2N5087, 2N5089, PN5129, PN5133,

PN5134, PN5137, PN5138, PN5139, 2N5210, PN5964 - 16, $1.55/10, $13.60/100

of some port no.

MPF102 .36 S30.60/C 2N5457 .48 $41. 00/C MPSA13 .28 124.00/C 2N3055 .99
$85.00/C

MOLEX PINS

Make your own 1C sodiets on PC board

,8S/C 8.20, /M 38.2Q/5M 27S,00/50M

SILICON DIODES

SLIDE SWITCHES
Smgle Pole Single Throw

.15 1.20/10 10.00/C

Double Pole Double Throw

.23 2.00/10 19.00/C

| BATTERY HOLDERS |

1- AA . . . 26c

2- AA . . . 42c

1- C _ 35c

2- C - 42c

1- D - 35c

2- D .... 42c

PERF BOARD

0.1" spacing belween holes

TERMINALS
for above perf board

SI. 50/C

LED LAMPS

NSL5053 T-l y« .18 SI 5/C
NSL5056 T-l V i .18 S15/C

LED DISPLAYS

FND357 CC .375" . . $1.75
FND500 CC .500" . . $1.75
FND 507 CA .500.. $1.75
FND800 CC 300" . $3.50
FND807 CA .800" . . $3.50

DATA BOOKS

BISHOP GRAPHICS Printed Circuit Drafting

Aide are now available from Digl-Key

RADIAL ELECTROLYTICS

22/50V. ..12 1.00/10
1 00/6.3 V . .09 .75/10
100/10V..10 .77/10

100/16V . .11 .85/10

10Q/25V . . 13 1.10/10
100/50V . . 21 1.71/10
220/10V..13 1.08/10
220/16V .. .15 1.16/10
220/25V . . 21 1.71/10
220/50V . . 29 2.35/10
330/10V . . 15 1.16/10
330/1 6 V.. 21 1.66/10

330/25V. .23
470/1 OR . . 21
470/1 6V. .23
470/2 5 V . . 29
1 000/1 OV. 24
1000/1 6V . 29
1 000/25 V. 42
2200/1 0V. 42
2200/1 6V . 54 '
2200/25V . 58
3300/1 6V. 89

AXIAL ELECTROLYTICS

.,14 1.15/J0
..19 1.52/10
..14 1.15/10
..17 1.30/10
.21 1.17/10
.14 1.13/10
.17 1.30/10
-.20 1.55/10
. . 29 2.30/10
..18 1.42/10
. 20 1.55/10
.. 29 2.35/10
. 40 3.23/10
.14 1.16/10

330/16V. . 29
330/25V . . 32
470/1 6 V.. 32
470/25V . . 37
1000/10V . 33
1 000/1 6V. 39
1 000/25V . 56
2200/10V . 50
2200/1 6V. 62
2200/25V . 79 i
3300/1 6V. 95
4700/1 6 V 1.09
1CC00/10V 1.15

y« & % WATT 5%
CARBON FILM RESISTORS

Sc each in multiples of S per valve
$1.70/100 A $12.00/1000 of tame valve

.64/10

5.50/C

S49/M

.66/10

5.60/C

S51/M

.68/10

5.B0/C

S52/M

.70/10

5.95/C

SS4/M

.82/10

7.05/C

S63/M

.90/10

7.75/C

S69/M

.99/10

8.60/C

S77/M

.40/10

3-50/C

S29/M

Doubfe Digit Discounts
Sove You Even Morel

RESISTOR ASSORTMENTS

r ZENER DIODES

ill/C IN5236B 7.5v .15 S11/C

ill/C 1N5237B 8.2v .15 Sll/C

m/C 1N5238B 8.7v .1 5 SI 1/C

ill/C lN5239B9.lv .15 Sll/C
ill/C 1N5240B lOv .15 Sll/C

ill/C 1N5241B llv .15 Sll/C

ill/C 1N52426 l?v .15 Sll/C

ill/C 1N5243B 13v .15 Sll/C

ill/C 1N5244B Uv ,15 Sll/C

ill/C 1N5245B 15v .15 Sll/C

l nA|

DATA BOOKS

nL IC's 595 p . 54.00

Linear IC's 957 p. 55.00
CMOS IC'i 256 p. S3. 00
Transistors 288 p. $3.00
Memory IC's 592 p. $3.00
Interface IC's 464 p. 54.00
Volt. Regs. 128 p. $3.00
Linear Appl, 1 432 p. 54.00
Linear Appl. 2 246 p. $3.00
Audio 196 p. $3.00

HARDWARE

2-56 1/4 Screw .99/C 7.20/M
2-56 1/2 Screw .99/C 7.65/M
4-40 1/4 Screw .55/C 3.60/M
4-40 1/2 Screw .60/C 4.05/M
6-32 1/4 Screw .65/C 4.40/M
6-32 1/2 5crew ,75/C 4.85/M
8-32 3/B Screw .90/C 5.85/M
8-32 5/B 5crew .99/C 7.00/M
2-56 Hex Nut .55/C 3.60/M
440 Hex Nut .55/C 3.75/M
«2 Hex Nut .60/C 4.00/M
8-32 Hex Nut .60/C 4.15/M
No. 2 lockwosher .85/C 5.75/M
No. 4 Lockwosher .45/C 3.00/M
No. 6 Lockwosher .45/C 3.00/M
No. 8 Lockwosher .45/C 3-X/M

I.C SOCKETS

8 Pin Solder .17 1.60/10

14 Pin Solder .20 1.90/10

16 Pin Solder .22 2.10/10

18 Pin Solder .29 2.75/10

24 Pin Solder .38 3.60/10

28 Pin Solder .45 4.25/10

40 Pm Solder .63 6.00/10

8 Pin W-W .24 2J0/10

14 Pin W-W .26 2.50/10

16 Pin W-W .30 2.05/10

18 Pin W-W .60 5.70/10

24 Pin W-W .96 9.10/10

28 Pin W-W 1.12 10.00/10

40 Pin W-W ,92 8.75/10

DOUBLE-DIGIT DISCOUNT SCHEDULE

S 0 .00-124.99 KFT S100.00-S499.99 Uw 15X
S500.00-S999.99 U» 50X
S2S.99-S99.99 Ins lax $1000.00 & Up ItU 2SX

Then Add the Standard Chary* Mtaw
STANDARD SHIPPING/ HANDLING CHARGE

S 0.00-S 4.99 .. aid $2.00 S 50.00-S99.99 . rid *0.25
S S.0Q-S24.99 , , rid S0.75 S100.00 & up . . He Char*
S25.00-S49.99 . . old $0.50

Mrit* diffli u4 dan *■ USA 4, Cmrii

COD ORDERS ACCEPTED FOR SAME DAY
SHIPMENT - CALL 11S-6A1-6674

U*d hr tn» *h
m «dl rvuhr’i

“Only Quality Components Sold!”
oont rcmoir ro awv wscount schiduu

DIGI-KEY CORPORATION

Box 677, Thief River Falls, MN 56701

DECEMBER 1976

CIRCLE NO. 23 ON FREE INFORMATION CARO

117

ARIES brought you the first calculator kit, and the
first digital clock kit . . . and now brings you three
of the most innovative electronic kits ever made.
The System 300 Electronic Music Synthesizer kit is
the most advanced in the world today, regardless of
price. The AR-781 is a space-age beauty for any
decor. And the wholly solid state AR-830 does
the work of a $400.00 tape memory unit.

O'7

WARNING ... if you're interested in a music syn¬
thesizer, don’t make a move until you see our cat¬
alog first. It’s more like a handbook than a catalog,
with hundreds of in-<lepth photographs and descrip¬
tions to explain electronic music principles, and to
show equipment to do the job, ARIES now offers
a complete complement of modules, keyboards, and
cases, matched to the most rigorous professional
standards. Starter systems priced as low as $395.00.

A clear, ruby-red cylinder

shows off all six digits of *

this modem calendar clock. ftjt

Easy-to-read numbers show /

the hours, minutes, and sec- ^

onds, as well as the month J ^

and day every ten seconds. *

Red LED 7-segment numerals are 0.33” high, in a
sturdy cylinder 2-1/2” in diameter and 4-3/4” long,
with finished hardwood ends. Time and calendar
are controlled by 60 Hz line frequency, with a 12-
month movement. Separate time and calendar adj¬
ustments. Includes all the components, PC boards,
housing, and instructions. Shipping weight 2 lbs.
AR-781 Clock Kit . . . $34.50

Add finger-touch operation - - — - - - - 1

to your old-fashioned dial
telephone with an ARIES
AR-830 Automatic Digital
Telephone Dialer. This has
the same layout and con¬
venience as Ma Bell, plus other features she doesn’t
offer yet. For instance . . . AR-830 always remem¬
bers the last number you dialed, in case the line was
busy and you want to try again later. Not only
that, but the Dialer’s memory can store as many as
ten of your favorite numbers for une-touch dialing.
AR-830 uses standard dialing and muting contacts;
consult local tariffs before connecting. Sh. wt. 2 lbs.
AR-830 Dialer Kit . . „ . $69.50

ARIES INC.

119 Foster Street
Peabody, Mass., 01960
<617) 532-0450

CIRCLE NO. 10 ON FREE INFORMATION CARD

ORGAN KITS
KEYBOARDS

THE ULTIMATE IN DESIGN
AND SOUND
FREE LITERATURE

Wurlltzer reproductions

tDEVTRONIX ORGAN PRODUCTS, Dept. C
5872 Amapola Dr.« San Jose, CA 95129

SURPLUS 'SMART’ TERMINALS, components, serious
music synthesizer kits, plans, parts, and more. Send SASE
for FREE INFO Package. CFR Associates, POBF, Newton,

N.H. 03856. _

CANADA’S electronics bargain centre. Free Catalogue.
North American and offshore inquiries welcomed. CAN-
MOS, Box 1690, Peterborough, Canada K9J 7S4.

FREE CATALOG. Calculators $4.95 each, Ultrasonic De¬
vices, Digital Thermometers, Strobe Light Kits, Memories,
Photographic Electronic Flash Units, Rechargeable Bat¬
teries, LEDS, Transistors, IC's, Piezoelectric Crystals,
Toroidal Cores, Unique Components. Chaney’s, Box
27038, Denver, Colo.. 80227.

Tips on top CB/Ham operation

Channel 51 magazine includes tips, articles.
MaSk! and step-by-step guidelines to improve your
CB/Ham operation. More meaty editorial per
? _ T. page than leading CB/Ham magazines! Learn

_ _ to build, repair, and professionally operate

± _ _ _ your own unit. And more! ForyourChannelSI,

_ send name, address, and SI. 50 now to:

Hufco Box 357, Dept. C51, Provo, Utah 84601 801/375-8566

CB RADIOS, monitors, crystals, CD ignitions. Southland,

Box 3591 -B, Baytown, Texas 77520. _

FERRIC CHLORIDE ETCHANT. 1/2 gallon $5.50. Gallon
$9.50. Postpaid. CIRCOLEX, Box 196, Marcy, N.Y. 13403.
DESIGNER MOTOR SET includes 1/40, 1/70, 1/150, 1/250,
1/500 horsepower. 3000 RPM. 115 VAC. $27 postpaid.
CIRCOLEX, Box 198, Marcy, N.Y. 13403. _

DIAGRAM SERVICE MANUAL, Television-Radio, sixteen
volumes, regular $62.50 value, only $19.95, postpaid.
Supreme Publications, 1760 Balsam, Highland Park, IL

60035. _

10, 7 Me 15 KHz Flltec miniature xtal filters, unused, $5
each. Polar Electronics, N3191 Horten, Norway.

fiiiimiHiimnmmn

pffifXJCT

• NEW MOS/ LSI TV GAME CHIP

GI-IAY3 BS00 1 In Slock
S TV Garnet on a singl# 1C

Unit Oty 39.95 «

Qty (5) 33.05

Oly (10) 79 95

• TV Kit 1 *PCS. Chip Instructions . #2.95 •

Video composite output

• TV Kit 2 *PCB, Chip, Switches. . 59 95

Capt, poti, tpeiker. ccyttal,
ale. and all pam required
for «idto output, instruction!

• TVK.t 3 Tha ultimate in TV . 99.95 |

Gamas, inc chassis, RF
modulator, battery operation,
partially assembled

. IS HERE!!! .

The Memory : ConcentrationfTiming Game.

Send SI .00 (refundable with order) for
illustrative information packet . . . includes technical description
circuit functions, component line-up, and game dynamics.

visulex P.O. Box 4204P Mountain View. CA 94040

130 PAGE detailed catalogue of European Electronic Paris
many not otherwise available, send $1 redeemable to: W.
A. Components, 65 Granby Street, Toronto. Ontario,
Canada M5B 1H6. U.S, Inquiries welcomed. _

BUILD YOUR 8VN SPEAKERS AND
SAVE UP TO 50%

You can assemble your own high Quality,
multi-element stereo speakers in a lew
hotirs and save up to hail the cost ol
comparable speakers Send for our tree
32-page catalogue ol speaker kits, raw
speakers and accessories

SPEAKERLAB

Oepl PE-0. SS00-3Sth N E

Seattle, Washington 08105

• ALTAI R/t MSA I COMPATIBLE 0K
LOW POWER STATIC RAM MOOULE
All the latest features at affoidabl*
prices.

includes 500 ns access lime requiring
no wait states, fully buffered,
memory write protect,
battery bock up. addressable
r/s on IK boundaries ie. 08K.

lb 1-9K, 2 10K etc., noise

rejection circuitry, dip switch
address selection

MPUTER

NEW PRODUCTS

• FUNCTION GENERATOR KIT . . 27 50

PCB, function chip, instructions,
and external components

• MULTlTELKIT . 50 00

PCB, instructions plus

Gl AY59100 push button dialer
AY 5-0200 repertory dialer
AY 3-9400 Multi Freq, gen.

AY5 9500 CMOS dock gen.

• TOUCHTONE CONVERTER S54.95

Converts dial phone to touchtone
completely assembled.

Special Introductory Price Only S2S9.00

• AMI EVK 99 6800 based Microcomputer Kit S149.00

Expandable to provide. EPROM
programming, 102# Bytes RAM. 2048 Bytes R
ROM. 2048 Bytes EPROM, lines, TTY,
selectable DMA. 5V. Kit consists PCB.

8800, 6850, 6820, 12) 6830, 14) 6810 1,

Operating manual and complete instructions.

Also Available . Tiny Basic tor 6800
Coming Soon . . . 16K RAM Add on memory
Write for More Details.

• 8080A Chip Set Special . . 79.95

1 - AMO 8080A

32 AMD 01 L 02 APC (500m*; Rams

Note: is hja? bftfl LyRdui-k- like vuu. If have -,-v *\i!. dlfl|' -■ ■ line and we will .i.o^vdi' how 10

• RAYTHEON • AMI

• RCA • INTERSIL*

• MM! • EAIM

ADVANCED MICROCOMPUTER PRODUCTS

I C MARKETPLACE

MICROPROCESSORS

AMD 8080A ....

AMD 2901 .

AMI 6800 .

Gl CP 1600 .

. $24.95
. 31.00
. 24.95
. 59.95

6800 SUPPORT DEVICES

S6860 Modem ....

S15.95

S6820 PIA .....

. 11.00

S681(M RAM « > * -

5.25

S2350 USRT ....

7.95

SI 883 UART ....

. 5.00

S6834-1 EPROM . . .

. 22.95

S6800 Prog. Manual . .

. 15.00

S6800 Hardware Manual

. 15.00

8080 SUPPORT PRODUCTS

8212 I/O Port. , . .

. S 3.75

8224 Clock .

5.00

8216 Driver ....

4.95

8226 Driver ....

5.95

8228 Controller , . .

8.90

9551 Prog. Interface. ,

. 19.95

9555 Prog. Interface , ,

. 19.95

7400 TTL O

GENERAL INSTRUMENTS
AY5-1013A Uart ..... S 5.25
AY5-1203 Clockcbip . . . 9.95

AY5-2376 Keyboard encoder . 15.00
R03-2513 Character Generator 10.95
Also available organ circuits, telephone,
timers, radio, TV, TV games, calculator
and printing calculator chips.

MEMORY DEPARTMENT
21 02 A PC (500ns.) . . S 1.70

21L02APC (500ns.) , . 1.89

2112 PC . 3.90

1702A . 10.90

DM8599 . 4.75

P3101 . 3.25

4402 (4 K Static) . . . 12.95

4200 (4K Static) . . . 13.95

AMD9130 . 13.95

AMD9140 . 13.95

PERIPHERAL CIR
75450 thru 453
1488 ....

14 89 A . . .
74LS138
8820N .

8830N .

8831 . .

8832 . .
8T26B .
9601PC .
9602PC .
9614PC .
9615PC ,
9616PC .

961 7PC .
9620PC .
9621PC .

751 07N .

751 08N .

751 09N .

751 ION .
75207N .
75208N .

• Tl • FSC • NSC • Gl

• SIEMENS • AMD

• SSS • EXAR • MOT

OUAD/DUALS/SPECIALS
RC1458CN .89

RC1556CN .99

RC3403AD 2.30

RC4131 CN .99

RC4136D 1.90

RC4558 CN .99

RC4151 CN 6.50

XR 2556CP 2.95

XR 2240CP 2.95

XR 1310P 2.95

XR 2206CP 3.95

XR 2207CP 3.75

XR 1800 2.95

XR 567CP 1.95

SENSE AMPS
7520N S2.50

75234N 2.10

DH3725CN 2.50

CLOCK DRIVERS
MH0026CN 4.50

SEND FOR OUR NEW CATALOGUE . . , it contains all
popular part types at competitive pricing.

1 We are not a surplus dealer and you will appreciate
our service when you get to know us.

TERMS: All shipments first class in U.S, for
orders under S25.00 add SI. 00 for handling,

Minimum order SI 0.00.

California Residents add 6% tax.

1-h itch p-°- BOX 17329

rUlcK IRVINE, CALIFORNIA 92713

118

CIRCLE NO 4 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

FREE INFORMATION:

Learning more about a
product that’s advertised
or mentioned in an article
in this month’s issue is as
simple as one, two, three.
And absolutely free.

Print or type your

name and address

on the attached,

postage-paid card.

Use only one card
per person.

Circle the num-
berfs] on the card
that correspond
to the numbeKs]
at the bottom of
the advertise¬
ment or article
for which you
want more infor¬
mation.

CKey numbers for
advertised prod¬
ucts also appear
in the Adver¬
tisers' Index.]

Simply mail the

postage-paid

card.

This address is for our product Free Informa¬
tion Service only. Editorial inquiries should be
directed to POPULAR ELECTRONICS, One

D-i »- Lr Awnmia Moiai Vorlf N Y IflDIfi

Use only one card per person

POPULAR ELECTRONICS "PE12763

• Use only one card per person

| name _

j ADDRESS _

CITY _ STATE _ ZIP _

(Zip Code must be included to insure delivery.) (Void after Feb. 28, 1977)

Do you build or assemble electronic equipment? □ Yes DNo
If yes, please circle number 1 ) From complete kits
K 2) From separate parts 3) Both

□ Please send me 12 issues of Popular Electronics for $6.99 and bill me.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

i "popular" E L E CTROnTcS PE12762

I Use only one card per person

NAME_ _

ADDRESS _ _ _

j CITY _ STATE _ ZIP _

(Zip Code must be included to insure delivery.) (Void after Feb. 28, 1977)

Do you build or assemble electronic equipment? CHYes ONo
R If yes, please circle number 1 ) From complete kits
} 2) From separate parts 3) Both

□ Please send me 1 2 issues of Popular Electronics for $6.99 and bill me.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

j POPULAR ELECTRONrds Ve1~2761

f Use only one card per person.

5 NAME _

• ADDRESS _

CITY _ STATE _ ZIP _

(Zip Code must be included to insure delivery.) (Void after Feb. 28, 1977)

Do you build or assemble electronic equipment? C]Yes QNo
r If yes, please circle number 1 ) From complete kits

2) From separate parts 3) Both

□ Please send me 1 2 issues of Popular Electronics for $6.99 and bill me.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

INFORMATION:

First Class
Permit No. 217
Clinton, Iowa

BUSINESS REPLY MAIL

No postage necessary if mailed in the United States
POSTAGE WILL BE PAID BY _

Popular Electronics -

RO. Box 2905 .

Clinton, Iowa 52732 - —

First Class
Permit No. 217
Clinton, Iowa

BUSINESS REPLY MAIL

No postage necessary if mailed in the United States
POSTAGE WILL BE PAID BY _

Popular Electronics ==

RO. Box 2905 ==

Clinton, Iowa 52732 , ■ , —

First Class
Permit No. 217
Clinton, Iowa

BUSINESS REPLY MAIL

No postage necessary if mailed in the United States
POSTAGE WILL BE PAID BY

Popular Electronics H==

RO. Box 2905 ==

Clinton, Iowa 52732 - - -

»mshb& arwasareaar

SPECTACULAR SOUND...

ON THE MOST IMPORTANT DISCS
IN YOUR ENTIRE COLLECTION!

A Remarkable Listening Experience

For Stereo Headphone Owners.

Binaural Demonstration Record

Binaural recording re-creates the directions, dis¬
tances, and even the elevations of sounds better
than any other recording method. The super¬
realism of binaural recording is accomplished by
recording the acoustical input for each ear sep¬
arately, and then playing it back through stereo
headphones. Thus the sound intended for the
left ear cannot mix with the sound for the right
ear, and vice versa.

Binaural recording offers the listener the iden¬
tical acoustical perspective and instrument
spread of the original. The sound reaching each
ear is exactly the same as would have been heard at the live scene.
STARTLING REALITY. The Binaural Demonstration Record offers 45
minutes of sound and music of startling reality. You’ll marvel at the
eerie accuracy with which direction and elevation are re-created as
you embark on a street tour in binaural sound — Sounds Of The City
. . . Trains, Planes & Ships ... a Basketball Game, a Street Parade,
a Steel Fabrication Plant, The Bird House at the Zoo — all demon¬
strating the incredible realism of binaural sound reproduction.

MUSIC IN BINAURAL. The musical performances presented on the
Binaural Demonstration Record transport you to the concert hall for
a demonstration of a wide variety of music. Selections total 23 min¬
utes, and include examples of jazz, organ, and chamber music.

The Stereo Review Binaural Demonstration Record is the ultimate in
sound reproduction. It has been made without compromise. $5.98

The Most Spectacular Sound Exhibition
Of Stereo Fidelity E ver Available
on One Disc And Cassette.

. MT.Kl.O
I)1.M<>\STR UK >\
KI.LOKl)

Stereo Demonstration Record And Cassette

The result of two years of intensive research in
the sound libraries of Deutsche Grammophon
Gesellschaft, Connoisseur Society, Westminster
and Cambridge. The editors of Stereo Review
have selected those excerpts that best demon¬
strate the many aspects of the stereo repro¬
duction of music. It’s the greatest variety of
sound ever included on a single disc or cassette.
Electrifying Experience in Listening. A series of
independent demonstrations designed to show
many aspects of musical sound and its repro¬
duction. Self-sufficient capsule presentations are arranged in a con¬
trasting and pleasing order, isolated and pointed up to give you a
basis for future critical listening.

Wide Range of Demonstrations, Techniques of separation and mul¬
tiple sound sources. Acoustic depth. The ambiance of a concert hall.
Sharp contrasts of dynamics. Crescendo and diminuendo. Very high
and very low pitched musical sounds. Polyphony (two or more mel¬
odies going on at once) with both similar and contrasting instruments.
Tonal qualities of wind, string and percussion instruments. Sounds of
ancient instruments. Sounds of oriental instruments. The singing voice,
both classically trained and untrained. Plus a large sampling of finger
snapping, hand clapping, foot stamping and other musical and per¬
cussive sounds.

13 Superb Selections. Strauss: Festive Prelude, Op. 61 (excerpt) DGG.
Debussy: Feux d'artifice (excerpt) Connoisseur Society. Beethoven: Welling¬
ton's Victory (Battle Symphony) (excerpt from the first movement) West¬
minster. Massaino: Canzona XXXV a 16 (complete) DGG Archive. Corrette:
Concerto Comique Op. 8 No. 6, “Le Plaisir des Dames” (third movement)
Connoisseur Society. Khan: Raga Chadranandan (excerpt) Connoisseur Society.
Rodrigo: Concert-Serenade for Harp and Orchestra (excerpt from the first
movement) DGG. Manitas de Plata: Gypsy Rhumba (complete) Connoisseur
Society. Marcello: (arr. King): Psalm XVI II "The Heavens are Telling” (com¬
plete) Connoisseur Society. Praetorius: Terpsichore: La Bourree XXXII (com¬
plete) DGG Archive. Berg: Wozzeck (excerpt from Act III) DGG, Bartok: Sonata
for Two Pianos and Percussion (excerpt from the first movement) Cambridge.
Beethovert: Wellington's Victory (Battle Symphony) (excerpt from the last
movement) Westminster. Booklet discusses and describes each selection.
RECORD— $5.98 CASSETTE-S6.98

HERE’S HOW TO ORDER

CASH: Mail your order along with your name, address and remittance in the
amount indicated above. Residents of Calif., Colo,, Fla., III., Mich., Mo.,
N.Y. State, D.C. and Texas add applicable sales tax.

CHARGE: To your American Express, BankAmericard, Master
Charge or Diners Club account! Mail your order, name, address,
credit card number and expiration date (Master Charge customers
include 4-digit interbank number above your name). Be sure your signature
is on your order. You will be billed in the amounts indicated above plus sales
tax, if applicable.

OUTSIDE U.S.A. RECORDS AND CASSETTES ARE $8 EACH

MAIL ORDERS TO: RECORDS, CONSUMER SERVICE DIVISION,

595 BROADWAY, NEW YORK, N.Y. 10012

Poly Pak7 EXCLUSIVE lifts S

100’S OF BARRELS PURCHASED!

For the first time anywhere, Poly Pak
merchandisers introduce a new way
in buying the economical way. Raw
stock from the "barrel". Remember
the "good ole days"7 They’re back
again. The same way merchandisers

YOUR

CHOICE

f ANY
KIT

throughout the United States buy
from various factories . . . their over¬
runs in barrels. Poly Pak has done
the same. Therefore you are getting
the same type of material as the
RE-TESTERS DO!

TEST 'EM YOURSELF ’N SAVE'

BARREL KIT #195

CARBO-FILM

RESISTORS

12E3534

75 for $1.98

millions. Lo & HI values,
Vt & Vb watt, G % , 10 %
tol. AH marked. 100%.

BARREL KIT #202
PLUGS, SOCKETS,
RECEPTACLES

100 for $1.98

Distributor unloads! In¬
cludes AC. DC, RF, audio,
4-9 pin, all kinds. Wt. 1 lb.

Cat No. 12E3S27

BARREL KIT #201
GV INDICATORS

w/leads

15 for $1.98

BARREL KIT #198 ftk
TRANSISTORS & IH
DARLINGTONS /Tl

50 for $1.98 HI

Motorola dumps 1,000,000
TO-220 in barrels. NPNs
& PNPs. All color-coded,
high yield. G ozs.12E3S33

BARREL KIT #141 A BARREL I
10 WATT ZENERS/*7 LAMPS, II

15 for cQ 20 for
$1.98 4°“* JR $1.98

Mfr dumps to prepare for Prcciaiotv

BARREL KIT #157
MOLEX CONNECTORS

lOOforrsasQ

$1.98

Nylon, white cable connec- j We gather*
tors, asst, factory over-run. | of clock cl
NO PICKEE! Mixed in bar¬
rets. Cat. No. 12E3324

BARREL KIT #140
LAMPS, INDICATORS

ir&HMte

new styling, voltages

over the place. Good yield, hardware.

metal, panel, with mtg

overstock. No. 12£3297

BARREL KIT #149
ROCKER S'

SWITCHES

25 for

$1.98 “<»*.tSar

Barrets ‘n barrels, so many,
our • customer* should get
the deal. No. L2E3302

PC, upright type, color cod¬
ed, V* watt. Asst values.
C»me to us in a barrel.

Cat. No 12E2746 1 00 %gOod,

BARREL KIT #68
2 WATTERS .

$1.98 100% good.

All marked. Cat.NoJl2E2735

Poly Paks C-R-A-C-K-S

TlliS prlces c

BARREL KIT #20
LONG LEAD DISCS

100 for —

$1.98 -

“nuruon sale”. Prime,
marked only. Long leads
Cat. 12E 2598 100 % good

□ SN7494N

□ SN7495N
D SN7496N

□ SN74100N

□ SN74106N

□ SN74107H
G SN74112N

□ SN74113N

□ SN74114N

□ SN74121N

□ SN74123N

□ SN74125N

□ SN74126N

□ SN74132N 1

□ SN74141N

□ SN74145N

□ SN74148N

□ SN74150N

□ SN74151N
n SN741S3N

□ SN7 4154N

□ SN74155N

□ SN74157N

□ SN741S8N

BUY 100
TAKE 25%

•?! 8 :S

,7i □ SN74164H .79

.98 □ SN74165N .99

65 □ SN74173N 1.39

.33 D SN74174N .97

.6S □ SN7417SN .89

.65 CSN74176N .79

.65 DSN74177N .79

.38 □ SN741B1N 2.05

.59 □ SN741B4N 1.75

.59 □ SN74185N 1.75

.59 □ SN74190N 1.15

1.00 □ SN74191N 105

.88 n SN74192N -87

.69 □SN74193N .83

1.29 □ SN74195N .73

.99 □ SN74196N .88

.70 □ SN74198N 1.49

65 □ SN74199N 1.49

1.03 □ SN74200N 3.95

70 □ SN742S1N 1.09

.70 □ SN742B4N 5.95

.85 □ SN74285N 5.95

BARREL KIT #4 BARREL KIT # 3

“4000" RECTIFIERS 1N4148/914

100 for SWITCHING DIODE

$1.98 Untested. IOC for $1.S

IN ion n series. May in- irnnninc Ititnous svvitc
elude 2"*. GO. 100. 200. diodes at these orices!

1N4 148/914
SWITCHING DIODES

lOO for $1.98

BARREL KIT #2
LINEAR OP AMPS, a

>ES dips 75 for A
98 tested $1.98 “

tching May jnriurie 709*s, 74
ls> 7 03 's, B 80 series. 6G6

■100, GOO. 80n and 1000 | Cat. Mb. 12E 241 8 Untested. | elude* Cat-No. 12E2416
yolters. X2E2417

lUl

BARREL KIT #5
SCRS, TRIACS^
QUADRACS £V

40 for^M

©Poly Paks 1 nc£‘ Wakefield, Mass., U.S.A. 1976

DECEMBER 1976

CIRCLE NO. 51 ON ffiEE INFORMATION CARD

BUILD YOUR OWN TV CAMERA 1
■ Ideal for home & business — I

THE ECONOMICAL ANSWER TO HOME MON¬
ITORING OF NURSERIES, ENTRANCES,

; DRIVEWAYS... BUSINESS and INDUSTRIAL
1 SURVEILLAHCE...ITV... AMATEUR TV PLUS

(HUNDREDS OF OTHER APPLICATIONS.
MODEL XT-IA, SERIES D - KIT FORM S1B5J
ASSEMBLED S$15. SOLID-STATE. WORKS ON
ANY TV SET. OPTIONAL SOUND KIT *23,95,
_ PHONE « WRITE for catalog. Dial N02-987-3T7I

1 1301 Broadway ATV Research Dakota city, wi. obtji

NON SEMI SURPLUS. Monthly picture flyer. Quality. Low
prices. Send 25 cents. U.S. only. Startronlcs, Box 683,

McMinnville, OR 97128. _

MICROCOMPUTER $90. Uses surplus components. Key¬
boards, IK RAM, LED readouts. Information $1. NBL-E,

Box 1115, Richardson, Texas 75080. _

DESIGN your own power supply and regulator circuits.
Twenty pages of circuit analyses and design examples.
8-1/2 x 11, $2.00. Midwest Design, Box 367, Harbert, Michl-
gan 49115, _

CB THEFT ALARM. Furnace thermostat timer. Random nite
light timer. Plans $2.00 each plus stamped, addressed
envelope. Don Hopman, 6537W Paradise Lane, Glendale,
Arizona 85306.

FREE FLYER from Colorado’s fastest growing electronic
parts distributor. Our second big year with outstanding
buys on kits, parts, semi’s, sciantiflc items. Visit our retail
outlet. J.B. Saunders Company, 3050 Valmont, Boulder,
CO 80301.

SCARE THIEVES AWAY, PROTECT CB GEAR
AND PROPERTY! Beautiful full color designs. /
made from weather resistant mylar, looks
like smokies! Use for; car, truck, boat, Vf//T
home, rv, ect. Complete CB ID. kit of jC\U
ten decals- ONLY $6.951! Write decals; /

CB CRYSTALS over 20,000 standard and specials In stock
from 6.0 MHz to 45.0 MHz. Call or write for information
package. Dealer inquiries invited. Roberts Electronics
Sales, 73563 29 Palms Highway, 29 Palms. California
92277. (714) 367-6235.

COMPUTERS-CALCULATORS: Parts, kits, interfaces, ter¬
minals, schematics, applications, programs, theory. Cata¬
log 50 cents, refundable. COMTEK, P.O. Box 401462D,
Garland, Texas 75040.

BARGAIN
BONANZA

ONLY
HIGHEST QUALITY
PRODUCTS

SURPLUS TUBES

ANY 3 FOR >1.49

Acquired from U.S. Defense depots or
removed from equipment (new and
used). These are laboratory tested and I
guaranteed for one full year. Most are of |
such standard makes as RCA, GE, etc.

6BJ8

6K6

18FW6

6BQ6

6K11

25L6

6BZ6

6LB6

35EH5

6CB6

6SN7

36AM3

□ (IP017) COPPER CLAD BOARDS!

Copper on one side, 1/16" thick. Ex¬
cellent quality for either production
or experimental work.

6¥a"xl7to" SI. 19 ea. 3/S2.99

□ Copper on both sides. 1/16" thick.
Size 12"xl8",

(IP018) $1.99 ea. 3/S4.99

□ (IP134) 8 ROTARY SWITCHES

Some multiple gang. $1,00

□ (IP128) 13 MINIATURE ELEC¬
TROLYTIC CAPACITORS $1.00

Axial & upright, popular values.

□ (IP144) TRANSISTOR

REPAIR KIT $1.19

Various parts used to repair trans¬
istorized devices.

□ (IP336) TO-3 TRANSISTOR

SOCKETS 12 for $1.00

□ 9 V. BUZZER
FOR ALARMS

99c ea. 6 for $5 V — -M*

□ (IP164) 4 ROLLS OF WIRE $1.00

Approx 25 ft. per roll, 20-28ga,

□ (IP140) TAPE RECORDER

SPARE PARTS KIT $2.95

Parts for repairing most tape record¬
ers: capacitors, meter, pilot lamp,
jacks, and MUCH MORE.

□ (IP167) 10 MINIATURE

POTENTIOMETERS $1.00

□ (IP182) 2 MISC. METERS $1.00

Miniature.

□ (IP156) 60 DISC

CAPACITORS $1.00

Asst, from .0001 to .1, most 600v,
Z5U, NP0, N750, etc.

□ FLAT WIRE RIBBON
CABLE

Useful for 1C connection
4 Conductor 25 ft $1.00

□ (IP155) TUBE BONANZA! $1.00

20 asst, popular tubes, untested.

□ (IP142) 50 PRECISION

RESISTORS $1.00

All 1%, tow and lw. low and high

ohmages.

□ (IP150) POWER TRANSFORMER

Primary 117 volts. Sec. 1-11.1 volts;
Sec.2 17.7 volts; Sec.3 15.9 volts;
Sec.4 27.7 volts. Each winding
approx. 750 mils. Size 2to"H x
2" D x 3to" mounting centers. $1.95

□ (IP175) 70 l/2w CARBON

RESISTORS $1.00

Asst, values. Some 5%.

□ (IP154) 150 CUT LEAD

RESISTORS $1.00

Carbon, all leads long enough for
soldering.

□ (IP149) 20 POLYSTYRENE TOP

GRADE CAPACITORS $1.00

□ (IP132) 20 DUAL POTS $1.00

^24^ C.T. FILAMENT
TRANSFORMER 1/2A.

* WITH 150V. TAP.

□ (IP202) 99c ea

6 for $4.99

MONEY BACK GUARANTEE

Terms: Minimum order $5.00. Include
postage. Either full payment with order
or 20% deposit, balance C.O.D.

□ BONUS
FREE CAPACITOR KIT

With Every $5 Purchase

□ WRITE FOR FREE 1976

VALUE PACKED CATALOG

Listing thousands of compo¬
nents, tubes, transistors, IC’s,
kits, test equipment.

ONTH’S SPECIALS!

18c □ 7446 80c

18c □ 7447 80c

22c □ 7448 80c

23c □ 7473 49c

23c □ 7474 49c

23C □ 7475 85c

23c □ 747 53C

23c □ 7490 79c

27C □ 7492 79c

40c □ 7493 69c

23c □ 7495 79c

23c □ 74121 57c

30c □ 74122 57C

$1.12 □ 74123 67c

LM309K 5v la. reg. $1.15

□ 555 Timer 75c

□ 556 Dual 555 S1.00

□ 566 Function gen. $1.75

□ 567 Tone decoder $1.95

□ 741 comp, op amp 39c

□ 2513 Char. gen. $5.95

□ 8038 volt cont osc $4.25

CLOCK CHIPS WITH DATA

□ (MM5314) 6 dig clock $4.95

□ CT7001 Alarm & Date $5.95

LED'S

□ (IP223) 10 Asst LEOs $1.00

□ (IP242) 5 Jumbo Green LEDs $1.00

□ (IP242 5 Med Yellow LEDs $1.00

□ (IP001 5 Jumbo Red LEDs $1.00

□ (IP011 5 Med Red LEDs $1.00

□ IP012) 5 Mini Red LEDs $1.00

□ (IP293) DL707 (equiv.) 7 seg
red LED, .3" char., comm

anode $1.50

□ (IP006) DL 704 (equiv.) same as

DL707 except comm cath $1.50

□ (IP007) DL747 7 seg red

LED, .6" char., comm anode $2.25

□ (IP013) MAN 5 (equiv.) 7 seg
green LED, .27 char.

comm, anode $1.49

1C BREADBOARDS & TERMINALS
Boards have .042 holes. Made of 1/16"
polyester glass.

□ (BB663) 3"x4" $1.16

□ (BB664) 3"x6" $1.34

□ (BB665) 4"x6" $1.65

□ (BB666) 4"x8" $2.12

Pusn-in terminals

□ (IP6601-20) pkg 20/90c

□ (IP66O1-I00) pkg 100/$2.98

Pusn-in flanged pins

□ (BB6602-20) pkg 20/90c

□ (BB6602-100) pkg 100/$2.98

Pusn-in flea clips

□ (BB6603-20) pkg 20/90c

□ (BB6603-100) pkg 100/$2.98

□ (B008) 14 pin DIP sockets 3 for $1

□ (IP1104) 1C REMOVAL AND

INSERTION TOOL $4.95

"Pul-n-sertic" extracts and inserts
ICS without damage.

REED RELAYS

□ (IP203) SPST, 12V, 1000 ohms coil.

Price 79c

Prices are subject to change without
notice.

EDUE ELECTRONICS, INC. 2700-IP HEMPSTEAD TPKE., LEVITT0WN, N.Y. 11756

1C BONANZA

•Data Sheat included on these items

Data Cassettes, Used,

Good Condition

S .98

•2102

IK Static RAM

1.49

•52030

Eraseable PROM 2K

10.95

•MM5330

National DVM Chip

9.95

•50310

Slide Rule Calculator Chip

3.95

*50250

Alarm Clock Chip

4.45

304H

Neg. Regulator

.95

309K

5 Volt Regulator

.95

7805

5 Volt Poa. Reg. (TO-220)

.79

7812

12 Volt Pos. Reg.(TO-220)

.79

7815

15 Volt Pos. Reg. (TO-220)

.79

MAN 7

(HP-7730) 7 Seg. Display

1.15

MAN 3

7 Seg. Display

5/1.00

MCA 8

Monsanto Opto Switch

.75

LED

.2 Red

6/1 .00

LED

.2 Yellow

5/1.00

LED

.2 Green

5/1 .00

LED

J2 Red-Right Angle

5/1 .00

LED

.12 Red

7/1.00

LED

.12 Yellow

6/1 .00

LED

.12 Green

6/1.00

Perforator Tape, per roll

7 Roll Carton

2.75

17.50

SEND FOR FREE CATALOG
Minimum order $5.00, data sheets 25 cents each.
Include 5% of order for postage and handling.
Texas residents include 5% state sales tax.

BONANZA ELECTRONICS

P. O. Box 24767 Dallas, Texas 75224

TAKII^I JUST ONE OF
lAINrx! THE 16 Gv4MES
\ YOU CAU PLkY WITH OUR NEW
i INCREDIBLE HAND HELDELEC-
'\ TRONIC GXME. SPECIAL

\ INTRODUCTORY ftC

\ PRICE only: *0.1/0

Sy SATISFACTION GUARANTEED
7 INTERFAB. 27963 CABOT RD.
S3 — LAGUNA NIGUEL. CA. 92677

REGULATED Power Supplies, New. Fixed and adjustable
one thru four outputs, T03 IC’s. Single 1A $14.95, Triple 2A
$27.95. Send $2.00 for brochure refunded on first order.
Mechelect, Inc., Box 911, Plymouth, Mass. 02360. _

NEW 6(y6QOMHZ PORTABLE COUNTER

• Urge .3" 7-Hglt LED dl»pl»y

• C-KOS 121 construction

• SaiU-ldotl for field use

• Portable batter; oparatad .

• With HiCad charger — . w

a Internal crystal tlaa beta ONLY
a Input* oearload protection

• 1 Hi raaolutlon on lou rang* $299

a 1 sag lnpot-aanaitialtj jjO w»

• 50 oho lnput-aanaltivlt; 100 m

• Si**: 2"H X 2.7S"W X l»"D

* 600 HHl FREQUENCY COtnfTEH THAT CAi OO AHYWHKRE - NOT A KIT

Dealer Inqulrle* Invited

CBS ENTER JTIISB P.O. BOX 13J6 COCOA «ACH FLA, 1M31

SURPRISES GALORE! Projects, ham radio, music synthe¬
sizers, etc. IC’s, pots, hardware, crystals, keyboards, re¬
sistors, etc. Send 13 cents stamp for catalogue. UTEP, Box
26231 B, Salt Lake City, Utah 84125.

$79.95 LIMITED TIME SPECIAL

B b K Model 2B0 Digital Multimeter
RegulaHyJfftgS'

■£:’> • 15% Discount on all other B & K items.
• FREE shipping in continental U.S.

• FREE 40 page catalog.

SPACETRON

BOX 84 -P • BROADVIEW, ILL. 60153

REVOLUTIONARY new electronics motor. 100 horsepower,
24V power source. ’’Digital-pulsed” and time -phased -pro¬
grammed. Motor block diagram and test data included. 550
mile range prototype test electric car. information, $3.50.
Wendell L. Daniels, Engineering Consultant, 8450 Anthony
Wayne Ave., Cincinnati, OH 45216.

Digital Clock Top Vehicles

As described in
Popular Electronics
fcfe. October 1976.

82 MS

+ $2.60 P&H
COMPLETE
KIT

LESS CASE

Kit includes all resistors, capacitors, transistors, diodes,
IC's, crystal, etched and drilled PCB, assembled display
board, switches, and step-by-step assembly instructions.

OPTIONAL CASE WITH LENS: $4.50.
COMPACT SIZE: 2.5" w x 1 J"h x 2.8"d
Outside U.S.A.: Add $3.00 P&H ordinary mail, $5.00 Air.

CIRCLE NO. 26 ON FREE INFORMATION CARO

POPULAR ELECTRONICS

ALTA J

25.50

KJt No. 70260-1 R (rad readout! I
K3t No. 702SOIG (Green mdouti)

Kft No. 70260-1 Y (Yellow readouts)

Kit No. 70250-2 R (DL727 raedouts) 3 in. $29.50

E-DIGIT ALARM CLOCK

THE KING FEATURES:

1> 6 digit . 12 hr. 60 cvcie or 24 hr

50 cycle alarm dock

11W. . 71 Tim* sharing capability for dia

i 10% tor Shipping play 0t additional information
31 Single 12v. supply and a mini
mum of interface component*.
4> AM-PM and automatic power fail
3 in. $29.50 ^ i^iMtion*.

5) 10 minute snooze

61 Intenjity control of LED*.

AllkJorndude components. PC Boards. Transformer. can. and construction manual.

THE KING'S HAREM

FATIMA 4-DIGIT TEMP. KIT

□ ELIL A >

(Example) Set your alarm for 7. a,m. , set irnwr
for 15 min, At exactly 7 a_m., the appliance
win start; it 7:15 your dock alarm will wake

TANVA BO HZ CRYSTAL TIME BASE

ADDITIONAL FEATURES.

1. ) Low Powsr Con tump lion

2. ) Directly Interfaces with King MOS Clock Chip.
X) 60 Hi output with crystal time base accuracy
4.) (deal for Cars, Boats, & Campers.

PND 70

RED. .25 In. Char.
16mA per segment.
Common Cathode.

•1.2*

New .5 in. display
by Fairchild.
Common Cathode.

FND603

11.60

S/T7.50

One of our best readouts
5 in. high, 20mA per
segment. Common anode.
S3.76

P N D BOO CATHODE »_■ 7

I k m Itifh. The Best BURROUGHS
I on the market. Ideal IB DIGIT

I rrsr~ jgrar*

Free tocket. 12.50

Mini red
Jumbo ted
Jumbo green
Jumbo yellow

Fully multiplexed common cathode.
Gold plated. Idea for mini Bdiqit
dock SI.3B

6 Boards containing 150 250 1C**

tf you like an
array of displays.

L we have it. Com
’ mon cathode.

•MS

GE TRANSISTOR ASSORTMENT
T09B cased Darling , SCRs.

. NPN.PNP.ect.
k 50 for SI. 50

100 for S2.50
X 300 lor 56.00

MSI

move

*M%#\

4-DIGIT dkcadk

COUNT!* KIT

SIS.”

KIT oia

One chip 4 digit decade counter

kit. with both 7 segment and BCD

output.

1. Chip features Infernal oscillator
for scanning speed.

2. Overflow and count extent out¬
puts.

1 Transfer, reset, count, blanking
and true compliment control in¬
puts.

4. PC Boards can be cascaded lo
8-12-16. etc. digits.

5. Kit Indudes counter chip, drive
circuit for 4 cathode type dis-
pfeyi and PC Bawd. (For read¬
out board see t FND 70 FNDS03)

MODULAR SCIENTIFIC
INSTRUMENTATION

Now you can build some of the most ,
menu with our new series of iow-ctOT
will expwrd the range of your electron!,
at a surprisingly low cost.

The heart of the system is our 4-digii
features a lull 4digit LED readout (you ,
application). Combine this with a 5-volt
and you have the basis ol a wide range
ments, including:

A Digital Voltmeter (DVM) .. Kit 012

Frequency Counter _ Kit 012

RPM Counter - Kit 012

advanced digital electronic instru
modular scientific kit*. These kits
c applications enormously— and all

Decade Counter (Kit 0121 which
choose the siie best suited to your
regulated power supply (Kit 0301
of sophisticated electronic instnj-

* Kit 030 ♦ Kit 017
e Kit 030 f Kit 016 *Tint* Base
S Kit 030 + Kit 020 + Kit 018

kit DIB FREQ. COUNTER

Feature* FET input front end w(th trigger circuit lor
measuring complex waveform*. Measures from 0.1 Hi to
lOMHi when usad with Kit 015 or 019. Measures from
.01 Hi to 35MHi when used with Kit 013 and 014.

S24.M

«?1

kit oao power supply

•Input voltage- 25V max. ’Output current. ! amp max,
*L0td regulation: 50mV 'Output voltage: 5V. line
regulation: .01%. (requires 8- 20V transformer)

34 55

(Contains all parts except transformer)

•Outputs .6 sac. 100th of RPM
6 sec." fOthol RPM
60 sec ■ lull involution

KIT 017 DVM

1,999V as banc, with poterity indication. 1 M ohm Input
impedance and accuracy to 1% if properly adjusted
StC.56

1 Mhr crystal chain time base divider. Outputs;
IMhr lOOKhi lOKhi IKhz-IOOHz IOHt-IHz-0. IHr.
Accuracy better than 005% with proper ad|UT merit

Kit 013 complete CMOS with PC board _ .- Si 5 75

Buffer Circuit for TTL Interlacing

Kit 01 4 Same as Kit 01 3, but with TTL _ *13.75

Kil 015 50Hi or 60Hz cham time base using line
frequence as reference Accuracy 0.1-0.06%. Outputs
IOHi lHz Q IRz. Complete with CMos thapmg or
cult and PC Board . 0.75

KIT 030 RPM COUNTER

Counts from 1 ro 100,000 RPM. RPM counter kit contains
components and PC t Kuril

SB 95

MSI

Send for your membership card to the Modular
Scientific Instrumentation Cluh and receive a
tf 19% all on future .turchase* of M-S.l kit*.
Send £3-00 with your name and Sddress We
will promptly tend your very own registered
membership card Don'i miss out on the
savings. Write now.

rshrps valid tor on* year Irom dale of registration

I N TEBRATID N

MM53I6 4-6 digit alarm clock 40 jun dip w/spec . .

7002 - 4 digit counter/latch decoder; 7 segment and

BCD outputs. 28 pin dip w/sp<rc . . .

7005 4 digit counter/latch decoder; 7 segment on :p*n

only. 24 pin dip w/spec . .

7007 4 digit counter/latch decoder with BCD output

only 16 pin dip w/spec . . . . . .

70250 - 4-6 digit alarm dock 28 pm dip w/spec . .

PC Board lor 70250 . .

70380 4 digit non-mu It ip lexed radio alarm clock

featuring direct drive display output 40

pin dip w/spec...- .

PC Board for 70380 . . . . . . .

TTL

8 bit parallel CPU . . .

IK static RAM for 8006 .

2K UV stateable PROM . - .

extinction calculator chip with direct
segment drive. 8 digit.... . . .

CMOS

'the TRAVELER'

4 DIGIT AUTOMOBILE CLOCK
FEATURES:

1. ) 5" Inch Ou plays

2. ) AC-DC Operated

3. ) Automatic Cut-In and Recharging

of Back-up Power Supply
A) Able to Ksap Tims Whila Changing
from Housa to Car or Car to Boat
Using Built-in Backup Power Supply
S.) Protected From Naira and Voltagt
Spikas In Car and Boat
fl-1 Direct Dr tv* Output*

7.) Non- Multiple xad Output Circuitry

COMPONENTS, PC BOARD.

TRANSFORMER, and
CONSTRUCTION MANUAL.

4-DIGIT

^ **-■-» 113 1 i ALARM CLOCK

** . 2S”

FEAT URE S:

Direci drive display miiiHiit, Currant control nnariaiion ini ehtp. * tow powijr Imijhincn
cnnlrpl ttn U|I|I • RFi nlnmnii|ln|t Stowuji tirctulry, • Sloop Radio htutum, - 24 hr snooze
alarm. " liuhniendaptl limit telling, 1 Non multiplexed outnut circuitry. 12VACCT 1/2 amji
Iranilorriwr lor Kit Nn. t

Complete kit with comfionents, PC Board. Transformer, wood
iram case and tilter for display window Inclwles .25 in
readouts gj a *|,b □

Complew kit with components, PC Board. Trrawtormer, wood
yam case, and filter for display window. Inchirie* ,5 inch read

ffiaa.ao

* Component* for Kit No. 2 or Kit No. 3 sleep radio feature, add US

4 & 6 DIGIT
PC BOARDS

PC Board to* 4 diflf T d*ni *% f *0*600 or 807
PC Board 6 d«rt dt*r F NO BOO Or 807
PC Bon*d td» A d-vt UAN ***** or 01707

S2 <sCv*r,f

PC fln «J- 4 <1.411 it mJjv DL777 O.

PC Ba-irn io> 6 *y,| a.vpiiv DL777 /■HB’ £1

PC 8t>«< i lor 4 ilf.1 rtiiuUv FND70 SI

All PC amlh bcarm «r* nwHipNtad *kkng WX* tonal cfcgtli

C s.I.I.I.M.I.I.I.i.,

J^IGHTS:-

AUSIC so WATT COLOR ORGAN

ALTAJ

ELECTRODES

P.D. BOX 31544 Oillat. Texas 7U3B
TERMS Chav k or money oxter No COO.

Telephone (214) 278-3561

* * Cal) Your Bank American] or Master Charge Order in on our
Continental United StatesfOLL FREE WATTS: 1-800-5274553.

555 Timer Mini dip
8038 Functional generator
RCA 3043 FM II. Aud Preamp
565 Phase Lock Loop
567V Tone Decoder
LM723 Po*. Volt. Reg.

LM309 5v. I amp Reg1
LM380 2w. Audio Amp. 8 pin dip
LM741 Operationet Amp.

TRANSIBTDRS-DIDDES

&> RCA200V 115W T05NPN 1.25

//r GE D40C1 NPN Dari. 0,25

V /*N. 2N4443SCR 400vBA T0220 0.65

J °7 2N2222 NPN Gen Ampl 0L20

2N3904 NPN Driver 0.15

2N3906 PNP Comp! 2N3904 0.15

'/ 2N4400 NPN Low level noise 0.20

ryv 2N5401 PNP Nixie driver 0-25

/// 1N4004 400PIV 15 (« 1D0

1N4007 4O00PIV 10 for 1.00
■yy 1N746 3.3 Zen. 4 for 1.00

r 1N4148 Switch 20 for 1.00

LOOK!

fiom Altai to you. a special ollri

Power Supply Kit: 5 Volt 1 Amp. Req.

Line regulation .005%

Load regulation 50tnV

Kit Includes Components. PC Board, Trans!.,
Fura, Pilot Light

Nothing else to buy. $6.50

DECEMBER 1976

CIRCLE NO. 7 ON FREE INFORMATION CARD

123

7400N TTL

.16 SN7459A .25

.16 SW7460N 21 SN74154N

.21 SN7470N .45 SN741S5N

.16 SH7472N .39 SN74156N

.18 SN7473N .37 SK74157N

.24 SN7474N ,32 SN74160N

.20 SN747SN .50 SN74161N

.29 SN7476N1 .32 SN74163N

.25 SN7479N 5.00 SN74164N

JS SN7480N .50 SW74165N

.1$ SN7482N .98 SN74166N

.30 SN7483N .70 SN74167H

.33 SN7485N .89 SN74170N

.45 SH7486N .39 SN74172N

.70 SN7488N 3.50 SN74173N

.35 SN7469N 2.25 SN74174N

.35 SW7490N .45 SN74175N

.21 SN7491N .75 SN74176N

.33 5N 7492N .49 SN74177h

.49 SN7493N .49 SN7410ON

.37 SN7494N .79 SN741BU

29 SN7495N .79 SN74182h

.29 SN7496N .89 SN74184fi

37 SN7497N 4.00 SN7418SP,

.42 SN74100N 1.00 SN74186A

.26 SN74107N .39 SN74187*

.31 SN74121N JJ9 SN74188f

.27 SN74122N .39 SN741907

,Z7 SN74123N .70 SN7419U

.25 SN74125N .60 SN741921

.15 SN74126N .60 SN74193F

.89 SN74132N 1.09 SN741941

.59 SN74136N .95 SN74195F

.75 SN74141N 1.15 SN741961

.75 SN74142N 4.00 SN741978

.75 SN74143N 4.50 SN74198I

■B1 SN74144 N 4.50 SN74199P

M SN74145N 1.15 SN74200P

.79 SN74147N 2,35 SN74279I

.26 SN74148N 2.00 SN74251I

.27 SN741S0N 1.00 SN742B4P

.27 SN74151N .79 SN74285?

.20 SN74153N .89 SN74367I

MANY OTHERS AVAILABLE ON REQUEST
20% Discount tor 100 Combined 7400's

1 CMOS ss

a C04035 1 85 74 C20N

2 5Q CD4D40 2 45 74C30N

25 CD4M 2 1 90 74C42N

jg CD4044 1 50 74C73N

59 C0404 6 2 51 74C74

.25 CD404 7 2 75 74C90N

.25 CD4049 79 74C95N

,47 CD4050 79 74C107N

56 CD4051 2 95 74C151

135 CO4053 2 95 74C154

55 C 04 060 3 2 5 740157

1 49 C04066 1 75 74C160

1.25 CD4069 45 7 4 C 1 6 1

25 CD4071 45 740163

1 .50 004 081 45 740164

.25 CD4511 2.50 74C173

.69 CD4518 2.50 74C193

1.65 CD4566 3.00 740195

2.90 74C00N .30 MC4044

.65 74C02H .55 MC14016

CONSUMER ELECTRONICS

LM301H 35
LM301CN 35
LM302 H 75
LM304H 1 00
LM305H 95
LM307CN .35
IM308H 1.00
LM30BCN 1.00
LM309H 1.10
LM309K .99
IM310CN 1 15
LM311H 90

LM311N .90
LM318CN 1 50
LM319N 1 30
LM320K-5 1 35

LM320K-5 2 1.35
LM320K-1 2 1.35

LM320K-15 1.35

LM320T-5 1.75

IM320T-5.2 1.75
LM320T-8 1.75

LM320T-12 1 75

LM320T-1S 1.75

LM320T-18 1.75

LM320T-24 1.75

LM323K-5 9,95

LM324N 1 60
LM339N 170
LM340K-5 1.95

LM340K-6 1.95

LM340K-12 1.95

LM340K-15 1.95

LM340K-18 1 95

LM340K-24 1 95

LM340T-5 1 75

LM340T-6 1.75

LM340T-12 1.75

IM340MS 1.75
IM340T-18 1.75

LM340T-24 1.75

LM350N 1.00
LM351CN .65

LINEAR

LM370N 1,1.5

LM373N 3.25

LM377N 4.00

LM380N 1.39

LM390CN 1.05

LM381N 1.79

LM382N 1.79

NE501K 8.00

NE510A 8.00

NE531H 3.00

NE536T 6.00

NE540L 6.00

NE550N .79

NE555V .45

NE560B 5.00

NE5618 5.00

NE562B 5.00

NE565H 1.25

NE565N 1.75

NE566CN 1.25

NE567H 1.95

NE567V 1.50

LM703CN .45

LM700H .29

LM709N .29

UI710N .79

UI711N .39

LM723H .55

LM733N 1.00

LM739N 1.00

LM741CH .35

LM741CN 25

LM74114N .39

LM747H .79

LM747N .79

LM74BH .39

LM748N .39

LM1303N .60

LM1304N 1.19

LM1305N 1.40

LM1307N .65

LM131GN 2 95

LM1351N 1 65

LM1414N 1,75

LM1458C 65

LM1496 N 95

LM 1556V 1 85

LM2111N 195

LM2901N 2 95

LM3065N 69

LM3900N 55

LM3905N 60

LM3909 1.25

LM5556N 1 B5

MC5558V 1.00

LM7525N 90

LM7535N 1 25

8036B 4 95

LM 75450 . 49

75451CN 39

75452CN 39

75453CN 39

75454CN 39

75491 CN 79

75492CN 89

75494CN 89

RCA UNEAR
CA3013 2 15

CA3032 2 56

CA3035 2.48

C A3 039 1 35

C A3 046 1.30

CA3059 3 25

C A3 060 3.25

CA30B0 85

CA3081 2.00

CA3082 2 00

C A3 083 1 60

CA3086 85

C A3 069 3 75

C A3 091 10 20

CA3123 2 15

CA3130 1.39

CA3140 1 25

C A3 600 1.75

RC4194 5.95

RC4195 3.25

SUPER PONG TJ!!8 $79.95

GAMES INCLUDED IN SUPER PONG ARE:

• PONG • CATCH

• SUPER PONG • HANDBALL

FEATURES OF PONG AND SUPER PONG

■ kicrwnwrtil speed or volley incrcaras excitertwnl.

■ Playing (eld adiusB to any see screen

■ G*tw appear m coloro/m Black 6 white. depend mg on television set.

■ Unmslakable PONG' sound accompanies each volley

■ Digital scoring Hashes an the screen between each point

■ 2 player challenge or Solitaire

■ Hooks up smply to any model television set; the screen actually becomes the playing l*ld

■ English and other techniques can be ised to make any member ol the laniiy a Pong champion

■ Baitery operated by 4 sire D Mshlight batwr*s included with the Unit

AC Adaptor (Eliminates Batteries) $9-95

PONG

mmf' □ ^3 ^3 S3 BE
iBBBBSG

128" fa.

XC209 Rid 107*1

XC209 Gran 4/SI

XC209 Orange 4*1

.280" to

XC22 Red 10/SI

XC22 Gran 4*1

XC22 YHtow 4*1

XC22 Onto* 4*1

SSL-22 RT 4*1

DISCRETE LEDS

.188" dli.

XCS26 Red 10*1

XCS26 Gran 4*1

XC526 Yea« 4*1

XC526 Orange 4*1

XC526 Ctear 4*1

XC556 Rad

XC556 Gran

XC556 Yellow

XC5S6 Orange

XC556 Cteir

DISPLAY LEDS

POLARITY

Common Anode
5 x 7 Dot Matrix
Common Cathode
Common Cathode
Common Anode
Common Anode-green
Common Anode-yellow
Common Anode-green
Common Anode -red
Common Anode
Common Cathode
Common Anode-yellow
Common Cathode -yellow

— XC111

XC1I1
XC111
XC111

.200” it
Rad 10*1

Gran 7*1

0*1 MV50

7*1 .085" dll. Micro

7*1 rad LED

7*1 6*1

POLARITY

Common Anode-orange
Common Cathode -orange
Common Anode-Red
Common Anode-rad *
Common Cathode
Common Anode
Common Cathode
Common Anode
Common Cathode
Common Cathode
Common Cathode
Common Caihode
Common Anode

1C SOLDERTAtL — LOW PROFILE (TIN) SOCKETS

25-49 50-100 1-

5 SDLDERTAIL STANDARD (TIN)

These switches feature seven SPST slide switches m a
mmm molded dip They are Ideally suited lot microprocessor
^ ^ applications g-j gg

CLIPLBTE ! ! 4//$1.00

NEW LED / ,,

MOUNTING SYSTEM f

• CLlPLITE mounts from the front
of the Panel In a .250 hole on 3/0"
centers. Panel thickness from 1/16" to 1/0".

• CLlPLITE equalizes and Increases the brightness of
commonly used wide beam LEDS.

• CLlPLITE is to be used with XC556 LEDS.

• Specify colors-red, preen, amber, or yellow whan
ordering.

ZENERS— DIODES— RECTIFIERS

TYPE VOLTS W PRICE TYPE VOLTS W PRICE
IN746 3.3 4 00m 40 00 1W005* 600 PIV 1 AMP 1W.Q0

1N751A 5 1 400m 4/100 1 N4006* 800 PtV 1 AMP 10/1.00 j

1N752 5 6 400 m 4/1.00 1H4007* 1000 PIV 1 AMP 10/1,00 !

1N753 6.2 400m 4/1.00 1N3600 50 200 m 8/1.00

1N754 6 8 400m 4/1.00 1N4148 75 10m 15/1.00

400m 4/1.00 1N4148 75

400m 8/1.00 1N4154 35

400m 4.1 00 1N4305 »

10m 12/1.00

25M 20/1.00

SDLDERTAIL STANDARD (GOLD)

WIRE WRAP SOCKETS (GOLD) LEVEL #3

24 pin

TCWff 28 pin

36 pin

.62 40 pin

15 400m 4.100 1N4305 7% 25M 20/1.0C

5 6 500m 28 1N4734 5.6 1w 28

6 2 500m 28 1N4735 6.2 1w 28

6 8 500m 28 1N4736 6.8 1w 28

7 5 500m 28 1N4738 8.2 1w 28

25 40m &100 1N4742 12 1w 2B

150 7m 61.00 1N4744 15 1w 28

180 10m 5/1.00 IN1 183 50 PIV 35 AMP L60

50 PIV 1 AMP 12/1.00 1N11B4 100 PIV 35 AMP 1.70

100 PIV 1 AMP 12/100 IN1 1 86 150 PIV nS AMP 1.50

200 PIV 1 AMP 12/100 INI 186 200 PIV 35 AMP 1.80

400 PIV 1 AMP 12100 IN1 188 400 PIV 35 AMP 3.00

WIRE WRAP TOOL Pait Number WSU 30 $5.95 ea

-n HEniMMi y mait ^

IJ ixtiir wwi Afrtot 1 I / -r

< ' (7) HUI 'oot \ ^

Q NU DOWMIMtO UOT WoNttlMIU 'g* ^

nm wet / /T) IWIOOI f

v7 (OUHHXUOUWm i- *

WIRE WRAP Wl

25 ft. min. -52.10 50 ft. -52.75 100 ft, -53.50 1000 ft. - 524.00

RESISTOR ASSORTMENTS $1.75 PER ASST.

SCR AND FW BRIDGE RECTIFIERS

10 OHM 12 OHM 15 OHM
27 OHM 33 OHM 39 OHM

68 OHM 82 OHM 100 OHM
160 OHM 220 OHM 270 OHM
470 OHM 560 OHM 680 OHM
1 2K 1 5K 1 8K

3.3X 3.9K 4.7K

1M 1.2M

2.7M 3.3M

18 OHM 22 OHM
47 OHM 56 OHM
120 OHM 150 OHM
330 OHM 390 OHM
820 OHM IK

1/4 WATT 5% 50 PCS.

1/4 WATT 5% - 50 PCS.

1/4 WATT 5X - 50 PCS.

1/4 WATT 5% - 50 PCS.

CAPACITOR

CORNER

.06 .05 .04
06 .05 .04
.12 .09 .073

Includes Resistor Assortments 1 -7 (350 PCS.) $10.95 ea.

XR-2206KA Kit

EXAR

XR-2260KB Kit

PHASE LOCKS! LOOPS WAVEFORM GENERATORS STEREO DECODERS MISCELLANEOUS

XR-2556CP 3 20 XR-S67CT 1.70

XH-2240CP 3.25

XR-205 8.40

XR-2206CP 4.49

XR-Z2G7CP 3.85

XR-1310EP 3.20 XR-4136 2 00

XR-180QP 3.20 XR-1468 3 85

XR-2567 2.99 XR-1488 5.80

XR-1469 4 80

XR-2208 5 20

data handbooks

7400 Pin out & Description of 5400/7400 ICS $2.95
CMOS Pin-out & Description of 4000 Series ICS $2.95
Linear Pin-out & Functional Description $2.95

ALL THREE HANDBOOKS $6.95

100 PER STRIP MOLEX PINS

Intended for use as an inexpensive substitute for 1C
sockete- Wso perfect for use as board connectors
llUfllli and M subassemblies.

SPECIAL — 100/1.49— 1000/12.00

All Advertised Prices Good Ttiru December
Satisfaction Guaranteed. 55.00 Min. Order. U.S. Funds.

California Residents — Add 6% Sales Tax — Data Sheets 25c each
\ Send a 24^ stamP (postage) for a Free 1977 Catalog

1021 -A HOWARD AVE., SAN CARLOS, CA. 94070

PHONE ORDERS WELCOME — (415) 592-8097

Ivliun 50 VOLT CERAMIC vUnllCI

DISC CAPACITORS

1-9 10-49 50-100 1-9 10-48 50-100

.05 04 03 001/iF .05 .04 .035

.05 .04 . 03 .0047fiF .05 .04 .035

.05 .04 .03 OVF .05 ,04 .035

.05 .04 . 03 .02 2mF .06 .05 .04

.05 04 .03 ,047*iF 06 .05 .04

.05 W .035 _VF .12 .09 .073

100 VOLT MYLAR FILM CAPACITORS
12 10 .07 022 ml .13 .11 .06

12 .10 . 07 047m( .21 .17 .13

.12 10 .07 imf .27 23 .17

12 10 .07 22ml .33 .27 .22

+ 20% DIPPED TANTALUMS (SOLID) CAPACITORS
.28 .23 .17 1.5/35V .30 .26 .21

.28 .23 .17 2.2/25V .31 .27 .22

.28 . 23 .17 3.3/25V .31 .27 .22

.28 .23 17 4.7/2SV .32 .28 .23

28 .23 17 6.8/25V .36 .31 .25

.28 .23 .17 I0/25V .40 35 .29

28 23 .17 15/25V 63 .50 .40

MINIATURE ALUMINUM ELECTROLYTIC CAPACITORS

.47/50V .16 14 .11

1.0/16V .15 13 .10

1.0/25V .16 .14 .11

1.0/5OV ,16 .14 .11

4.7/15V .15 13 .10

4.7/25V .15 .13 .10

4.7/SOV .16 .14 .11

1Q/16V 14 .12 .09

10/25V .15 .13 .10

10/50V 16 14 .12

47/SOV .24 .21 .19

100 /16V 19 15 -14

22/2SV 17 15 .12

22/50V .24 .20 .18

47/2SV .19 17 .15

47/SOV 25 .21 .19

100/25V 24 . 20 .18

100*W 35 30 ,2B

22D/50V .45 .41 .38 100/25V

470/25V ,33 29 . 27 100/50V

1000^6V .55 .50 .45 220/16V

.24 .20 .18

.35 .30 .28

.23 .17 .16

.31 28 .26

124

POPULAR ELECTRONICS

■^§1 CRYSTALS \W—\ MICROPROCESSOR COMPONENTS

— these frequencies only 1 — I _

prf?

Frequency

CaiB/Sfyle "

Prlce^

CY1A

1.000 MHz

HC33/U

$5.95

CY2A

2.000 MHz

HC33/U

$5.95

CY3A

4.000 MHz

HC18/U

S4.95

CY7A

5.000 MH2

HC18/U

S4.95

CY12A

10.000 MHz

HC18-U

$4.95

CY14A

14.31516 MHz

HC18U

S4.95

CY19A

18.000 MHz

HC18.U

S4 95

CY22A

20.000 MHz

HC18U

54 95

CY3DB

32.000 MHz

HCIS'U

S4 95

CLOCK CHIPS — CALCULATOR CHIPS

MM 5309 6 Quit. SCO Outputs. Reset PIN. $9.95

MM531 1 6 Digit. BCD Outputs. 12 or 24 Hour 4.95

MM5312 4 Digit. SCO Outputs. 1 PPS Output 4 95

MM5314 6 Digit. 12 or 24 Hour. 50 or 60 Hz 4 95

MM531E 4 Digit. AH mi. 1PPS Output 6 95

MM531B Video Clo<* CWp, For Use WWt MM5S41 9.95

CT7001 6 Digit. CaUmter, Alarm. 12 or 24 Hour 5.95

CALCULATOR CHIPS

MM5725 6 Digit, four Function. Less Decimal S2 95

MM 5738 8 Digit. 5 Function + - * - 2 95

CT5Q30 12 Digit 4 Function ana •» ’ 95

25-PIN CONNECTORS

D-Subminature

DB25P MALE $3.25 each

DB25S FEMALE $4.95 each

Vector W«»tg Pend PI 73 consols ot i rand held I wtherwerght (under one ounce)
toot wtucft is used to guide and wrap nsulaedwtre. fed oft a sett -contained leptaceatue
bobM onto component leads or letnunals installed on pte- punched P Pattern
Vector bold* Connections between the wrapped wim and component t^ pads or
I temWots are made by soMetng Complete with 250 FT of ted wire #7 ne

REPLACEMENT WIRE — BOBBINS FOR WIRING PENCIL
W36-3-A-Pkg. 3 250 It 36 AWG GREEN SI .95

W36-3-B-Pkg. 3 250 ft 36 AWG RED St .95

W36-3-C-Pkg. 3 250 It 36 AWG CLEAR S1.95

W36-3-D-Pkg 3 250 ft 36 AWG BLUE St .95

V*:*;v>. 1/16 VECTOR BOARD

7”.\* O.t" Hole Spacing P-Pattem Pnce

Pin No L vV 1 2-Up

PHENOLIC 6JP44 M2XXXP 4 50 6 50 1 72 t 54

t69P44 02XXXP 150 ?7 00 3.69 3 32

EPOXY 64P44 062 4 50 6 50 2 07 I 86

GLASS 84PJ4 062 4 50 8 50 2 56 2 31

1 69P-U 062 4 50 17 GO 5 04 4 53

169P84 062 8 50 17 00 9 23 8 26

cPtl'YC,^^ I69P44 062C1 4 50 17 00 B 80 6 t2

m HEAT SINKS

205-CB Beryllium Copper Heal Smk with Black Finish lor TO-5 .25

291-.36H Aluminum Heat Sink lor T0-220 Transistars & Regulators .25

680-.75A Black Anodized Aluminum Heal Sink lor TO 1 1.60

NIBBLING TOOL DIAGONAL CUTTER

■ ,, * V," Semi -Flush Col Rite Odgoul

M u’

8080 SUPPORT DEVICES

8212 8 B IT INPUT/OUTPUT PC RT FC R 8080

8216 NON INTERRUPT BI-DIRECTIONAL BUS DRIVER
8224 CLOCK GENERATOR AND DRIVER FOR 8080
8228 SYSTEM CONTROLLER AND BUS ORIVER FOR 80

CPU’S Ml

8 BIT CPU $19 95 ttOt 256* 1 !

Super 0008 24 95 1103 1024 *1 I

Super 6008 34 95 2101 256* 1 I

«H‘S 2102 1024 il t

1024 Dyname S 9 00 2107 4096 * 1 I

Hex 32 flrT 7 00 2111 256* 4 |

Hex 40 BIT 4.00 7010 1024 1 1 I

512 Dynamic 2.49 7409 16 * 4 j

1024 Dyname 6 00 8101 256 * 4 1

Dial 256 BIT 3 95 8111 256 * 4 >

Do* 512 BIT 4 00 8S99 16*4 <

OuadBOBtT 3 95 91L02 1024 *1 !

1024 Static 7 95 74200 256 » 1 !

Frfo 6 95 93421 2S6 x 1 !

16 * 4 fleg 3 95 MM5262 2K * 1 [

U ART'S Pf

DOKBaud S5.95 I702A 2048 F

nDM'S 5203 2048 F

Char Gen S 9.95 82S23 32 x 8 C

S 5.95 8 0 80

7 95 S24.95

12.95 *

12.95

256 Bn (32 * 8) Open Collector 2
256 Br)( 32 * 81 Three State 2
1024 Bit (256 * 4) Open Coleaor 3
1024 Bit (256 « 41 Three State 3
2048 Bit (512 * 4) Open Wweor 9

BIPOLAR PROM SPECIAL

2 95 6306- t

6306- 1 2048 Bit (512 x 4) Three State 9.95

6340- 1 2048 Bn (512 * Bt Open Colleclcr 19 95

6341- 1 2048 Brt (512 * 8) Three State 19 95

6352- 1 4096 Brt (102 x 4) Open Collector 19 95

6353- 1 40% Brt (1024 x 4) Three State 19 95

This 0-2 VDC .05 per cent dlQiiaJ voltmeter features the Motorola 3W digit
OVM chip set. It has a 4" LEO display and operates from a single +5V
power supply. The unit is provided complete with an iniection molded black
plastic case complete with Bezel. An optional power supply is available
which fils into the same case as the O-ZV OVM allowing 1 1 7 VAC operation.

A. 0-2V DVM with Case $49.95

B. 5V Power Supply $14.95

c VECTOR WIRING PENCIL

Nibbling Tool SG.95 UqM Blue Hindi!

Replacement Punch $3.75 Each A97MS S8.50 ea.

63 KEY KEYBOARD codedSPSTkeys unattached to

any kind ot P C B A very solid
mowed plastic 13" * 4" base
suns mosl ao oi cations

$19.95

HD 01 65 16 LINE TO FOUR BJT PARALLEL KEYBOARD ENCODER

JOYSTICK

These joysticks feature four *
potentiometers, that vary re¬
sistance proportional to the
angle of the stk*. Sturdy metal
construction with plastics
components onty at the mova¬
ble Joint. Perfect for electronic
games and instrumentation.

*5K Pots $6.95
*100K Pots $7.95

Continental Specialties

Proto Boar* 100 ... nE n

$19.95 “no |

DIGITAL WATCHES

Ladies Watch

• 6 Function

• Bracelet Styling

• 1 Year Guarantee

• Model 900

• Specify Gold
or Chrome

$69.95

€

EXELAR Mens Watch

• 5 Function

• Quartz Crystal

• Black Leather Band

• Manufacturer Guarantee

• Specify Gold
or Chrome

$29.95

DIGITAL QUARTZ CAR CLOCK

Complete kit tram mounting bracket ot the injectxm maided case
doww to 0» three conductDr poww cord and a8 components bt-
durtrg MM531 4 dock (ftp. Fwtures quartz accuracy ol .01%,
to* Agri. .35" high LED display, and P C Boards. Works on
any 12 wit system — motorcycles, boats, vbis, moto rhemes,
autos, and trucks.

DIMENSIONS: 4 V x 4" x 2M - 12 OR 24 HOUR MOOE.

Assembled: S39.95

DIGITAL CLOCK KIT — 3V2 INCH DIGITS

4 DIGIT KIT S49.95
6 DIGIT KIT S69.95

4 DIGIT ASSEMBLED S59.95
6 DIGIT ASSEMBLED S79.95.

Satisfaction Guaranteed. S5.00 Min. Order. U.S. Funds.

California Residents — Add 6% Sates Tax — Data Sheets 25? each
Send a 24c Stamp (postage) tor a FREE 1977 Catalog

*ss ha mss

1021 -A HOWARD AVE., SAN CARLOS, CA. 94070

PHONE ORDERS WELCOME — (415) 592-8097

DECEMBER 1976

CIRCLE NO. 40 ON FREE INFORMATION CARD

HQ CB RADIO

nfw mi irR.fii

--T ^3 $99.95

NEW IDI 1CB-630

23-Channel Synthesized CB Transceiver

SIZE: 6% (W) x2" (H) x BYx
POWER INPUT: 5 Watts/1 2-Volt Max.

POWER OUTPUT: 4 Watts RMS

MOBILE CB ANTENNA $24.95

BASE LOAD - FIBERGLASS WHIP KA-2401

Mounts on Hood or Trunk Lid

AMTEX 8 TRACK AM/FM STEREO
FEATURES $69.95

■ 6 track stereo player «■* j »

■ AM/FM mpx radio 1

■ Advanced 1C construction V **

■ Dial on door and slide-bar swtlch type

■ Compact — only 1-25/32" (45mm) high. 4-13/16" (122mm) deep. 6-11/16"
(170mm) wide and 5 position adjustable shah distance.

■ Complete in -dash type design

■ Easily adjustable antenna trimmer lor best performance

KRACO CAR SPEAKERS $14.95

Flush Mount 10 Oz. Mag. IB ohm Model SST-101F

5 FUNCTION ELECTRONIC CALCULATOR
RADOFIN MODEL 8P

$8.95

• 8 Oiflil Display

• 5 Functions cons 6Bo! addition, subtraction, mul-
tipltcaion. divfiion. peromtige. with constant on
all functors, won full floating decanal Pont

• Pwrer source is 1 pwee 9V OC Battery OOGP.
lack lor AC adapter

• Black superfine gramed finflh plastic eabmrt

5 FUNCTION ELECTRONIC CALCULATOR WITH
WALLET-NOTEBOOK AND POCKET CHECKBOOK
RADOFIN MOOEL 1710

FEATURES $19.95

. 8 Oigrt display I HH I

» 5 FunciiorEcorcstsaladditnn. subtraction, mul¬
tiplication. orveon. percentage, with constant on
all functnns, with lull Holing decrial point
• Power source s 6 AAA celts 9 V DC
■ Wallet b 2 lone texon. cabinet b black plastic

D'GITALALARM NoVUS

This 4 digit Novus Alarm Dock
is a very reliable and smartly
styled unit. It provides such
features as an alarm settable
to any minute of the day. a
minutes snooze alarm, a power
(allure indicator, and even an
A. M., P.M. indicator.

$17.95 NOT A KIT

JE700 CLOCK

The JE 700 ts a low cost digital dot*, but
o a very luglt quality unit The unit fea¬
tures a snutated walnut case with di¬
mensions ot 6 *2*7 *1 Itutilizesa
MAN 72 high brightness readout, and the
MM5314 dock chip

115 VAC $17.95

- - This large digit dock ( 6' hours &

minutes. 3" seconds) features the
MM5314 dock chip. It operates
from 117 VAC, and will operate in
either a 12 or 24 hour mode. The
dock is complete with a walnut
grain case, and has fast set. slow
_| set. and hold time set features.

KIT - ALL COMPONENTS & CASE $34.95
WIRED & ASSEMBLED S39.95

JE803 probe T"^

Ttw Logic Probe is a unit wfiu. h >; 'or ihe most part f

mdespensiS’e m trouble snooting logic tern »«. / *

TTL DTL RTl CMOS li OenvtrS the power <1

needs to operate directly oh ot (he circuit under -

test drawing a scan? 10 mA max It uses a MAN3
readout to ■ idicate any of tne toiiowing slates by

these symbols iHj- 1 (LOWi- olPULSLt P The — _ — ■

ProOc can detect nighlreguency pulses to 15 MHr Ipy.jjD rwi Ml
It can t be used at MOS levels or Circuit damage

w.tt result printed circuit board

'This dock features btg 3’? high digits
tor viewing m offices auditoriums etc
Each digit is termed by 3t Dnqm 0 2
LEDs The clock operates horn 1 17 VAC.
• has either 12 or 24 hr operation The 6
Conversion is 27 *3'r * 1 ' » andlhe
4 digit is 18 *3’? * 1!?" Kits come
complete with an components case and
transformer

Specify 12 Ot 24 Hr. When Ordering

T*L 5V 1A Supply

This is a standard TTL power suoply using the well known
LM309K regulator ic to provide a solid 1 AMP ol current at 5
votts We try to make things easy tor you by providing
everything you need in one package including the ha tdware

,oronly $9.95 Per Kit

± 5 VOLT POWER SUPPLY
$3!

Completely Assembled
* + 5 Volts @ 6 Amps
Regulated Output
i -5 Volts @ 6 Amps
Regulated Input
> 6.3Volts @ 5 Amps
Unregulated Output
Length BW x Width 6 W
x Height 4” L/m/fed

HAPPY HOLIDAYS HOBBYISTS

A GREAT GIFT pjp |\/|jnj|jjp lo-profile rackets 10/51.60 j

“Electronic PrcJectslJb^

BY CRAIG ANDERTON; now in 2nd printing. This
book has shown thousands of people how to as¬
semble electronic projects. 7^ saYs "a dandy |
book. .. fantastic music gadgets". Popular Elec¬
tronics says "gets it all together". Electro¬
notes says "highly recommended. . .it gives the
essential information". Tells how to build 19
music ian/audiophile projects. With soundsheet.

100 PIN EDGE CONNECTOR- -NEW I

Specify wirewrap (il

'or soldcrtail. Pe r £e |fj(lj |

IMS A I r-^***!^ $5 EACH

machines. OR 5/ $22

1 BILL GODBOUT ELECTRONICS

BOX 2355. OAKLAND AIRPORT, CA 94614

TERMS; Add 50C handling to orders under j
$10. Cal res add tax. No COD; to place
BankAmericard* or Mastercharge* orders,
call (415) 562-0636, 24 hours. I

5/S1.95
2SV
1000 uF

[Standard
(phenolic
I type.

I LTD QTY

A “rice"

figTpd maxTf

t 25°C it

\ $4.95

3.5W

J $5.95

8.7W

f $6.95

21W

1 $7.95

29W

IOuF, 450V1SV
_ 3/51 |t0-3 Sockets

I EFFICIENCY REMARKS
2 Oil

Sim. to RCA 2NS470
Sim. to RCA TA8407
Sim. to RCA 2N6269
Factory selected
r) part — 2N6269

) i} wmu utnnnruoouuuunu t r

Right angle, 24 pin card edge connector (
for .062" (single-sided) cards. 0.156"!
i spacing between leads. LIMITED QTY.

lIl-SOBOA and 8-2102L1S. Uses LOW power j

memories, guaranteed 450 ns over full |
comm, temp range. Factory new parts. I
(2102L1 available separately . S 1 . 95 J

8080A available separately . $20 . 95 S

UHF

transistors

CIRCLE NO. 32 ON FREE INFORMATION CARD

NEW TS1755/GRM test sets for PRC25. $30 shipped in U.S.
Free catalog. BRAND X, Rt. 3, Box 223-11, Ontario, OR

97914. Dealers Inquiry. _ _

FLYING helmets, headsets with boom microphones,
adapted to CB’s. Amplifier, 10139 Apache, Richmond, VA
23235. _

PLANS AND KITS _

FANTASTIC — Solderless breadboard kit with all parts for
fascinating experiments with Flasher / Oscillator f Siren
chip $12.95 less battery. Catalog 50 cents (refundable).
Satisfaction Guaranteed. Ego, Box 1331 -pb, Thousand

Oaks, California 91360. _

FIVE OCTAVE Touch Sensitive Electronic PIANO KIT.
Components $229 airmail U.S.A., Canada. Clef Products,
31, Mountfield Road, Bramhatl, Cheshire, England SK7

ILY. _ _

RECHARGE dry cells without electricity, batteries or solar.
Simp la -in expensive. Send $2.00 for plans. Thayar, 2775

N,E, Wiberg Lane, Portland, Oregon 97213. _

TAPE-SLIDE Synchronizer, lap-dissolve, multiprojector,
audiovisual plans, $0.50. Sampler, $1.00. Millers, 1096 May-
wood. S. Euclid, OH 44121. _

TIGER SST
. ^SIMPLI-KIT

For US

BE on

faster Zl

P all

service CO

DE mail

0 R SJI -

THE DO-IT-YOURSELFER
NOW’- a high quality CD Electronic
Ignition System in kit form.

Contains all components and solder to
build complete Solid-Stete Electronic
CD Ignition System for your car. As¬
sembly requires less then 3 hours.

* Increases MPG 1 5% * Eliminates 4 of 5 tune-ups

• Increases horsepower 15% • Instant starting, any

•Plugs and Points last weather

50,000 miles • Dual system switch

Fits only 12 volt neg. ground . . . Only $21 .95 postpaid
■ ■ - r-m in- Star Corporation ■

P.O. Box 1727 Grand Junction, Colorado 81501

1.85 2SC76715.75

1.75 2SC773 .85

1. 10 2SC774 1.75

3.75 2SC775 2.75

4.75 2SC776 3.00
3.80 2SC777 4.75
3.90 2SC778 3.25
4. 15 2SC797 2.50
4.25 2SC798 3.10

I 4.75 2SC781 3.00
l .70 2SC789 1.00
.70 2SC796 3.15
i .70 2SC799 4.25
i 3.00 2SC802 3.75
i 9.50 2SC803 4.00
i 10. 15 2SC839 .85

2SC866 5.85

2SC013 1.50

2SC1014 1.50

2SC1017 1.50
2SC1018 1.50
2SC1173 1.25
2SC1226A 1.25
2SC1237 4.50
2SC1239 3.50
2SC1243 1.50
2SC1306 4.75
2SC1306-1 4.90
2SC1307 5.75
2SC1307-1 6.00
2SC1377 5.50
2SC1449 1.30

2SC 1449-1 1.60 40081
2SC475 1.50 40082

2SC1908

2SC1957

2SF8

OEM SPECIALS

JAPANESE TRANSISTORS

1.50 40082

3.00

1N270

.10

2N960

5.50 2SC608

4.85

1N914

.10

2N962

4.75 SK3046

2.15

2N967

2.15 SK3047

3.75

2N173

1.75

2N1136

2.15 SJ2095

3.50

2N178

.90

2N1142

5.50 SK3048

3.25

2N327A

1.15

2N1302

.70 SK3054

1.25

2N334

1.20

2N1305

1.50

2N336

.90

2N1377

3.00 2SK19

1.75

2N338A

1.05

2N1420

13.25 2SK30

1.00

2N398B

.90

2N1483

1.00 2SK33

1.20

2N404

.30

2N1540

3.00

2N443

1.75

2N1543

3.00 3SK40

2.75

2N456

1.10

2N1544

3.00 3SK45

2.75

2N501A 3.00

2N1549

1.25 3SK49

2.75

2N508A

.45

2N1551

STAm

* i

2N555

.45

2N1552

2SA52 .60

2SA316 .75

2SA473 .75

2SA483 1.95
2SA489 .80

2SA490 .70

2SA505 .70

2SA564 .50

2SA628 .65

2SA643 .85

2SA647 2.75
2SA673 .85

2SA679 3.75
2SA682 .85

2SA699 1.30
2SA699A 1.75
2SA705 .55

2SA815 .85

2SA816 .85

.70i2SC815 .75

.70 2SC828 .75

.80 2SC829 .75

2.50 2SC830 1.60

1.60 2SC839 .85

.80 2SC945 .65

.75 2SC1010 .80

.65 2SC1012 .80

.70 2SC1051 2.50

2.50 2SC1061 1.65
1.00 2SC1079 3.75

.80 2SC1096 1.20

1.75 2SC1098 1.15

3.50 2SC1115 2.75

3.75 2SC1166 .70

.70 2SC1170 4.00

2.50 2SC1172B 4.25

2.10 2SC1209 .55

2.50 2SC1213 .75

2.35 2SC1226 1.25

.70 2SC1243 1.50
.70 2SC1293 .85

.70 2SC1308 4.75
.70 2SC1347 .80

.70 2SC1383 .75

1.75 2SC1409 1.25
1.90 2SC1410 1.25
1.00 2SC1447 1.25

.70 2SC1448 1.25
1.00 2SC1507 1.25
2.50 2SC1509 1.25

2SC1569 1.25
2SC1756 1.25

2SD151 2.25
2SD170 2.00
2SD180 2.75
2SD201 1.95

2SD218 4.75
2SD300 2.50
2SD313 1.10
2SD315 .75

2SD318 .95

2SD341 .95

2SD350 3.25
2SD352 .80

2SD380 5.70
2SD389 .90

2SD-390 . 75

2SD437 5.50

MPS-U31 4.00
M PS-8000 1.25

2N652A .85

2N677C 6.00
2N706 .25

2N706B .40
2N711 .50

2N711B .60
2N718 .25

2N718A .30
2N720A .50
2N918 .35

2N930 .25

2N956 .30

2N1554 1.25
2N557 .15

2N1560 2.80
2N1605 .35

2N1613 .30

2N1711 .30

2N1907 4.10
2N2060 1.85
2N2102 .40

2N2218 .25

2N2218A .30
2N2219 .25

2N2219A .30
2N2221 .25

2N2221A .30
2N2222 .25

2N2222A .30
2N2270 .40

2N2322 1.00
2N2323 1.00
2N2324 1.35
2N2325 2.00
2N2326 2.85
2N2327 3.80
2N2328 4.20
2N2329 4.75
2N2368 .25

2N2369 .25

2N2484 .32

2N2712 .18

2N2894 .40

2N2903 3.30
2N2904 .25

2N2904A .30
2N2905 .25

2N2905A .30
2N2906 .25

2N2906A .30
2 N 2907 .25

2N2907A .30

2N2913 .75

2N2914 1.20
2N2916A 3.65
2N3019 .50

2N3053 .30

2N3054 .70

2N3055 .75

2N3227 1.00
2N3247 3.40
2N3250 .50

2N3375 6.50
2N3393 .20

2N3394 .17

2N3414 .17

2N3415 .18

2N3416 .19

2N3417 .20

2N3442 1.85
2N3553 1.50
2N3563 . 20

2N3565 .20

2N3638 .20

2N3642 .20

2N3643 .15

2N3645 .15

2N3646 .14

2N3730 1.50
2N3731 2.75

2N3740 1.00
2N3771 1.75
2N3732 1.90
2N3773 3.00
2N3819 .32

2N 3823 . 70

2N3856 .20

2 N 3866 .85

2N3903 .20

2N3904 .20

2N3905 .20

2N3906 .25

2N3925 3.75
2N3954 3.50
2N3954A 3.75
2N3955 2.45
2N3957 1.25
2N3958 1.20
2N4037 .60

2 N 4093 .85

2N4124 .20

2N4126 .20

2N4141 .20

2N4142 .20

2N4143 .20

2N4220A .45
2N4234 .95

2N4400 .20

2N4401 .20

2N4402 .20
2N4403 .20
2N4409 .20
2N4410 .25
2N4416 .75

2N4441 .85

2N4442 .90

2N4443 1.20
2N4852 .55
2N5061 .30

2 N 5064 .50
2N5130 .20
2N5133 .15

2N5138 .15

2N5198 3.75
2N5294 .50

2 N 5296 .50
2N5306 .20
2N5354 .20

2N5369 .20
2 N 5400 .40
2N5401 .50

2N5457 .35

C103Y .25

C103D .40

C106B1 .50
C106D1 .75

SILICON UNIJUNCTIONS

INTEGRATED CIRC.

RECTIFIERS

100

2N2646

.50

2N2160

.65

UA703C

.40

2N2647

.60

2N4870

.50

709C OP. AMP.

.25

IN4001

.60

5.00

2N6027

.55

2N4871

.50

741C OP. AMP.

.25

IN4002

.70

6.00

2N6028

.70

2N4891

.50

7400

.15

IN4003

.80

7.00

D5E37

.25

2N4892

.50

TA 706 IP

3.50

IN 4004

.90

8.00

2N4893

.50

TA 7205P

10.00

IN 4005

1.00

9.00

2N4894

.50

UPC 1001h2

6.00

IN 4006

1.10

10.00

MU 10

.40

NE 555

1.25

IN4007

1.20

11.00

POWER-TRANSISTORS HIGH-VOLT. TV. TYPE

BU204 1300V 3.90 BU207 1300V 5.40 2SC1172B 1100V 4.25

BU205 1500V 4.70 BU208 1500V 6.25 2SC308 1100V 4.95

BU206 1700V 5.90 2SC1170 1100V 4.00 2SC1325 1100V 4.95

New-Tone Electronics
P.O. Box 1738 A
Bloomfield, N.J. 07003
Phone: (201) 748-6171, 2, 3

ALL PARTS GUARANTEED AND TESTED ON PREMISES.

N.J. residents add 5% sales tax. Minimum order $5.00. All orders
add $1.00 postage. Dealers write or phone for discount prices.

126

CIRCLE NO. 45 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

6 Digit LED Clock Kit - 12/24 hr.

<095 QTY.12 <1095 QTY. <1195 OTY.

** ea. OR MORE IUea 6-11 Ilea. 1-5

KIT INCLU DES Ref- com. cathode)

• INSTRUCTIONS 13-Transistors . a one A fllfilTQI

•QUALITY COMPONENTS |l^olritors ^nonVp l."

•50or60 Hz OPERATION 5-Diodes

• 12 or 24 HR OPERATION 9-Resistors AN INCREDIBLE VALUE!

• l Z OT MHUrLHAIIUN 24-Molex pins for 1C socket

“Kit #850-4 will furnish a complete set of clock components as listed.
The only additional items required are a 7-12 VAC transformer, a circuit
board and a cabinet, if desired.”

Printed Circuit Board for kit ft 850-4 (etched & drilled fiberglass) . $2.95

Mini-Brite Red LED's (for colon in clock display) pkg. of 5.. . *”*]* 1.00

Molded Plug Transformer 115/10 VAC (with cord) . 2.50

NOTE: Entire Clock may be assembled on one PC Board or Board may be cut to remote display.
Kit It 850-4 will fit Plexiglas Cabinet II.

MOBILE LED CLOCK

120R 24-HOUR OPERATION
12 VOLT AC or DC POWERED FOR FIXED
OR MOBILE OPERATION.

SIX JUMBO .4” DIGITS!

KIT OR ASSEMBLED

PLEXIGLAS

CABINETS

Great for Clocks
or any LED Digital

CABINET 1

project. Clear-Red
Chassis serves as

3"H,6%"W,5H"D

Bezel to increase
contrast of digital

CABINET II

displays.

Black, White or

2J4"H,5"W,4"D

Clear Cover

ANY SIZE/COLOR

$6.50 ea 2/M 2.

1 RED OR GREY PLEXIGLAS FOR DIGITAL BEZELS 1

3”x6”x1 /8”

95* ea 4/*3 I

6 Digit-LEO Clock-Calendar-Alarm Kit

MODEL

2001

ACCURATE TIME
WITH ADJUSTABLE
XTAL TIME BASE

53 0154

Approx. Size:

1 % "H x4"W x4’/2 "D

BATTERY BACK-UP
FOR POWER FAILURE
OR TRANSPORTING
FROM HOUSE TO CAR. ETC.

This is a complete, top of the line, Kit Tor the person that wants the
best. Some of the many features and options are: 12/24 time,
28-30-31 day calendar, alternates time (8 sec) and date (2 sec) or can
display time only and date on demand, 24 hr alarm - 10 minute
snooze, alarm set indicator, 50/60 HZ. line operation or use with Xtal
time base (#TB-1), built in OSC for battery back-up / AC failure, Aux.
timer. Larae digits.

Kit #7001 B 6- .4" Digits Man-64 $39.95

Kit #7001 C 4- .6" Digits &2-.3" (seconds) $42.95

Kits are complete (less cabinet) including PC boards, power supply,

1C socket, 9 switches, 16 transistors and all parts required for above
features and options (Ideal fit in Cabinet I above).

• 6 JUMBO .4" RED LED'S BEHINO REO FILTER LENS WITH CHROME RIM.

• SET TIME FROM FRONT VIA HIOOEN SWITCHES • 12/24- Hr. TIME FORMAT

• STYLISH CHARCOAL GRAY CASE OF MOULDEO HIGH TEMP. PLASTIC

• BRIOGE POWER INPUT CIRCUITRY - TWO WIRE NO POLARITY HOOK-UP

• OPTIONAL CONNECTION TO BLANK OISPLAY (Us* When Key OH in Car, Etc.)

• TOP QUALITY PC BOAROS& COMPONENTS - EXCELLENT INSTRUCTIONS

60 HZ.

XTAL TIME BASE KIT

Will enable Digital Clock or
Clock-Cal. Kits to operate

PRINTED CIRCUIT BOARDSfor CT-7001 Kits sold
separately with assembly info. PC Boards are drilled
Fiberglass, solder plated and screened with component
layout. Specify for #7001B or 0 7OO1C (Set of 2) $7.95

KIT *2001

COMPLETE KIT 251?? 3

(Less 9V Batteryl EA M0RE

ASSEMBLED UNITS WIRED & TESTEO
ORDER *2001 WT (LESS 9V. BATTERY]

$27”

$39”

60796 Assembled Units

EVO# EA Ma* Be Mixed With

^0* JUMBO RED LED's 12/$1.00 50/$3.95

Clock-Cal. Kits to operate JUMBO DIGIT CLOCK KIT

from 12VDC. Uses MM5369 ^ complete Kit (less Cabinet) featuring: six .5" digits,
and 3.58MHZ. XTAL. Req. MM5314 |C, 12/24 Hr. time, 50/60 HZ., Plug-Transformer,
5-15VDC/2.5 MA. 1"x2 PC Line Cord, Switches, and all Parts.

Board. Easy 3 wire hookup [|dea( F|t |n Cabinet $1 Q95

Accuracy: + - 2 PPM Kit#53i4.5. . . . !3ea

#TB-1 [adjustable]

Complete kit $4.95 ea
Wired & Cal. $9.95 ea

SCHOTTKY TTL

74500 < .35

74501 .40

74504 .55

74505 .60

74509 .56

74510 .40

74S15 .55

74S20 .50

74S22 .45

74S40 .45

137 .09

LED DRIVERS

.40 7447
.55 7448
.50 75491
.45 75492

74 Iso M VOLTAGE

74S51 .55 REGULATORS

74S64 5S LM309H TO-5 *
lit* I!! LM309KTO-3 1-25

74S75 ire 7805 TAB 95

74S78 1.50 TAB 1-25

” 7806 TAB

£ 7812 TAB

7.cdc S 7815 TO-3

74S107 95 7815 TAB

IS « 781-15 TO- 5

74S113 T40 78f JO’3

5 * ™

74S133 .75 DIG

74S134 .75 CLQC

74S138 1.75 UUJL

74S139 1.50

74S151 1.95 53 2

74S153 1.95 ^5314

74S156 1.95 WM5375A

74S156 1.95 CT 7001
74S157 1.80 CT 7002
74S158 2.50

74S174 2.50

74S175 2.50

74S181 2.95

74S182 1.95

74S251 2.75

DIGITAL
CLOCK IC’s

AY5-1013 > 6.95

DIODES

IN 4002

1 A. 100 PIV

12/S1.00

IN 4003

1 A, 200 PI V

12/SI. 00

IN 4005

1 A. 600 PI V

11 /si. 00

IN 4007

1 A. 1000 PIV

10/S1.00

RECTIFIER 2.5A.1000PIV

4/ $1.00

RECTIFIER

3A. 1000 PIV

3/S 1.00

IN 5400

3A.50PIV

5/S 1.00

IN 914

SIL. SIGNAL

20/SI. 00

IN 4148

SIL. SIGNAL

20/S 1.00

DIAC

28V.

4/S1.00

PLUG

TRANSFORMERS

12 VAC at 150 M A

S 2.50

12 VAC at 500 MA

3.50

LINEAR

555 TIMER

2/SI. 00

556 DUAL TIMER

.95

565 PLL

.95

566 FUNCTION GEN.

1.75

567 TONEDECOOER

1.75

1C SOCKETS

PINS

1-24 25

100

S .25 > 22

8 .20

.28 .25

.23

.31 .28

.26

.50 .45

.40

.60 .55

.50

.75 .70

.65

MEMORY

2102-1 IK RAM

$1.95

21L02

$2.35

TRANSISTORS

2N2222A TO 18 5/<1,00

2N3415 TO -92 5/S1.00

2N3704 TO -92 5/$1.00

2N4249 TO-92 5/S1.00

2N4400 TO 92 5/ >1.00

2N4437 TO-92 5/S1.00

2N5089 TO-92 5/S1.00

ROCKER SPDT 6/SI.
MINI SLIDE SPOT S/91.
REG. SLIDE DPDT 6/51.
PUSH BUTTON N.0.3/S1.

TRANSISTOR SOCKET
TO-5/18 GOLD PINS

5/51.00

NYLON WIRE TIES
8" TIE-WRAP 100/51.95
4" TIE-WRAP 100/51.75

MOLEX PINS

REEL OF 1000 5 8.50
STRIP OF 100 1.25

OP AMPS

3/51.00
301 OIP
301 TO-5
709 OIP
741 DIP
741 M-DIP
741 TO-5

747 OIP

748 TO-5

DISCRETE
LED's
JUMBO REO

PC TRIM
POTS

25K 6/51.00
4.7 K 6/51.00

SPECTROL

10K10TURN

JUMBO DIGIT CONVERSION KIT

Convert small digit LED clock to large .5” displays. Kit
includes 6-. 5” LED’s.Multiplex PC Board & easy hook-up Info.

Kit #JD-1CC For common Cathode 1(185 O/HO

Kit #JD-1CA For common Anode “ ea. 4/1 U,

Fairchild Super Digit | see the works Clock Kit

Clear Plexiglas Stand

9^, .4" C*ur. Ht. _ .. .. _ _ _

7 ifqmtni led *6Big .4 digits
K: KD0if«Tr *12 or 24 hr. time -r— —

■t rfpi»cwn« hi for *3 set switches (back) ~ ■ * S >

popular fnd-70. ,piug transformer 23 M5 09

95^ ea, 10/S8.50 •ajiparts included I is? M J| I
100/S79.00 Plexiglas is

Pre-cut & drilled , t

Size:6’H,4Yj’’W,3’’D

SET OF 6 FND-359

WITH MULTIPLEX
PC BOARD $6.95

25 AMP BRIDGE
^ ^ $1.95 ea.
3/$5.00

I00P1V

TELEPHONE FORMAT
KEYBOARD
BY Chomerics

ASUPER LOOKING
CLOCK!

Kit #050-4 CP

*23“ 2/*45.

§ 7-SEG LED

** COMMON CATHODE

COLOR HT.DECPT. PR.EA.

MISC. PRIME IC’s

FAIHCHILD 9316 (74161) S .95
75234 DUAL CORE SENSE AMP 1.50
MM 502H TO-5 SHIFT REG .95

OARD COLOR

jmerics FND-359 RED
FND-503 RED
2-1 / 4"x3” DL-750 RED

XAN-654 GREEN
5/32" thick XAN-664 RED

.4" RHDP $ .95
.5" RHDP $1.35
.6" LHDP $2.95
.6" NDP $2.95
.6" NDP $2.95

BUY 100 OR MORE IC's lAny Mix] TAKE 10% DISCOUNT.

OFTOE1ECTRDNIGS. sc.

BOX 219 • HOLLYWOOD, FLA. 33022 • (305) 921-2056

$4.95
6/*28

ORDER BY PHONE OR MAIL
COD ORDERS WELCOME
f SI .00 CHG.l

Orders Under $15 Add $1.00
Handling

Fla. Res. Please Add 4%
Sales Tax.

WE PAYALLSHIPPING IN CONTINENTAL USA- OTHERS ADD 5% [ 10% FOR AIRMAIL)

COMMON ANODE

DL-747 RED .6" LHDP $2.95

XAN-72 RED .3” LHDP $1.25

XAN-81 YELLOW .3" RHDP $1.75

XAN-351 GREEN .3" RHDP $1.50

XAN-361 RED .3“ RHDP $1.50

XAN-362 RED .3" LHDP $1.50

XAN-662 RED .6" NDP $2.50

X AN -692 RED .6" NDP $2.50

Form Inexpensive MOLEX t

Sockets PINS

100 for $1.25 j

Reel of 1000- $8.50

DECEMBER 1976

CIRCLE NO. 48 ON FREE INFORMATION CARO

127

«*BS

Under-Dash Jyp j

LOCK MOUNT ITS

yfc. AU-344 U-—

^^3'1" "*9

Locks player in place. Slides in &
out. 6 x 13/16 x 7". 6 or 12 VDC.
Shipping weight 2 lbs.

Monitor
L^Pl3 Converter

• Covers Channels
1 Thru 23

Rea # Converts AM auto
" ■ * radio to CB

I AA monitor. 12 VDC

in HH neg. grnd. Styles
I ■ may vary. Shpg.

| fCB-417 wt. 2 lbs y

40-Minute
Recording
Tape ta-907

C Blank tapes.
Erased, not
used. Shpg.
Ea. wt. 1/2 lb.

Three

60-Minute

Blank

Cassettes

TA-879

i- 99

PARTS t COMPONENTS
V4 RPM Timini Motor, 117 V. AC
1 RPM Timini Motor, 117 V. AC
8 RPM Reversible Motor, 117 V. AC
Tubular Capacitor Kit, 100 Pcs.

Ceramic Capacitor Kit, 100 Pcs.

100 Ceramic Capacitors, values clearly marked
50 Asst. Electrolytic Capacitors, Axial/Radial
100 Asitd. Carbon Resistors, %-%-1 Watt Sizes

5 Asstd. SCR’s, 15 V. and Up, 100 MA to 1.6 AMP
500 MW Zener Diodes, 4.3-6.3-9.1-12 fc 15 Volts
3 Unijunction Transistors, 40 V. 375 MW. 4 ON/S
L.E.0. Pkg. of 5 Red, 2 Volt - 5 MA
Ultra-Mini L.E.D. Pkf. of 5 Red, 2 V. 5 MA

Tl Calculator Key Board, 20 Keys
3Ya Difit Liquid Crystal Display
Darlington Amp. Transistor Kit, 6 Transistors
Photo Transistor, 5 Pieces - Epoiy Type

6 Amp. Full Wave Bridge Rectifier 50 PIV
6 Amp. Full Wave Bridge Rectifier 400 PIV
PNP Transistor Assortment Pkg. of 10
NPN Transistor Assortment Pkg. of 10
7-Segment L.E.D. Display .3 In. Green
7-Segment L.E.D. Display .3 In. Red
7-Segment L.E.D. Display .3 In. Yellow
Micro Type Switch Kit, 7 Assorted

Knob Kit, 25 Pcs. Assorted
Hobby Motor Kit, 3-6 V. DC, Pkg. 5

TOOLS — SPECIAL AND PRACTICAL
Wire Wrap Tool, 30 Ga Wire on .025 Post
1C Insertion/Extraction Tool
1C Plug-in Test Adapter
12 Volt DC Soldering Iron, Pencil Tip
Tuner/Contact Cleaner, 6 Oz. Can
Dymo Label Maker. Uses % In. Tape
Double Face Foam Tape % x 52 In.

180 minutes
of recording
time. Shpg.
wt. 1/2 lb.

REG.

SALE

MO-277

.49

.30

MO-289

.49

.30

MO-393

2.50

.99

CC-229

2.00

1.29

CC-211

1.49

1.19

CC-210

1.29

.80

CD-407

5.00

2.00

RR-077

1.79

1.00

TR-298

1.79

1.00

01-052

1.00

.50

TR-441

1.29

.50

PL-233

1.19

.60

PL-289

1.29

.70

XM-523

5.00

1.60

XM-371

10.00

3.00

TR-507

2.00

1.50

TR-502

1.00

.60

01-057

1.20

.80

01-058

1.90

1.00

TR-445

1.00

.60

TR-446

1.00

.60

XM-341

2.69

1.00

XM-370

2.00

1.00

XM-342

2.49

1.00

SW-430

1.89

1.49

KN-030

1.00

.69

MO-333

.59

.49

TL-B45

2.60

2.00

TL-846

1.25

1.00

TE-396

2.60

2.00

TL-793

4.00

3.00

TL-459

1.49

.80

TL-752

1.89

.90

TA-903

1.00

.80

OLSON ELECTRONICS, 250 S. FORGE ST. O ^
DEPT IS AKRON, OHIO 44327

NAME _

ADDRESS _

CITY _ STATE.

□ SEND OLSON CATALOG

□ SHIP THE FOLLOWING

_ ZIP _

□ FREE PA CATALOG

STOCK

NUMBER

DESCRIPTION

PRICE |

EACH TOTAL

World’s Lowest
1C Prices

* SPECIAL PRICES

MEMORIES

Rama

2102 1.50*

Proms

62S23JS123 1.95*
TTL

7400 .12*

HIGH SPEED
74HOO .20

74HD1 .20

74H04 .20

74H10 .20

74H11 .20

74H40 .20

74H51 .20

74HS2 .20

74H74 .40

74H103 .50

74H1D6 .50

LOW POWER
SCHOTTXY
74LS00 .29

74LS02 .29

74LS0a 29

74LS10 .29

74LS27 .30

74LS73 .45

74LS75 .65

74LS151 1.10

74LS153 1.10

741S157 1.10

74LS161 1.50*

74LS163 1.50

74LS164 1.50

74LS174 1.10*

74LS175 1.50

74LS193 1.50

74LS221 1.50*

74LS251 1.50

74LS253 1.50

74LS257 1.50

74LS25B 1.50

Order Mmmum $10 00 AM $1 00 shipping and handing charge per order C ahforma residents add 6°e sales
f as All orders shipped Fust Class withm 24 hours

Order Ihe limoui lasts 6 volume Programmed Learning Course "Microcomputer Design is s Snap" lor
S99.S0 and receive a special S10.00 credit on iny group ol IC’a.

Salisfaclion 100*. guaranteed. C.O.D. Order*: Ptione (day or night) 408/354-1448

ClTDnkl AP0 B0X 2542

V.LI r\\yl i Sunnyvale, CA 94087

Free monthly catalog— Just send us your name and address

CLTRON

CIRCLE NO. 29 ON FREE INFORMATION CARD

■=AB0UT YOUR
SUBSCRIPTION

Your subscription to Popular
Electronics is maintained on one of
the world's most modern, efficient
computer systems, and if you’re like
99% of our subscribers, you'll never
have any reason to complain about
your subscription service.

We have fouhd that when com¬
plaints do arise, the majority of them
occur because people have written
their names or addresses differently
at different times. For example, if
your subscription were listed under
‘•William Jones, Cedar Lane, Mid¬
dletown, Arizona,” and you were to
renew it as "Bill Jones, Cedar Lane,
Middletown, Arizona,” our computer
would think that two separate sub¬
scriptions were involved, and it
would start sending you two copies
of Popular Electronics each month.
Other examples of combinations of
names that would confuse the com¬
puter would include: John Henry
Smith and Henry Smith; and Mrs.
Joseph Jones and Mary Jones. Minor
differences in addresses can also
lead to difficulties. For example, to
the computer, 100 Second St. is not
the same as 100 2nd St.

So, please, when you write us
about your subscription, be sure to
enclose the mailing label from the
cover of the magazine — or else copy
your name and address exactly as
they appear on the mailing label.
This will greatly reduce any chance
of error, and we will be able to ser¬
vice your request much more
quickly.

POPULAR ELECTRONICS

S. D. SALES CO.

P.O.BOX 28810 D
DALLAS, TEXAS 75228

4K LOW POWER RAM BOARD KIT
THE WHOLE WORKS
$89.95

Imsai and Altair 8080 plug in compatible. Uses low power static
21L02— 1 500 ns. RAM's, which are included. Fully buffered,
drastically reduced power consumption, on board regulated, all
sockets and parts included. Premium quality plated thru PC
Board.

Stick It!

IN YOUR CLOCK!
IN YOUR DVM, etc.

HUGE SPECIAL PURCHASE!
NOT FACTORY SECONDS
AS SOLD BY OTHERS

$3.95

BUY 3 FOR $10.00

4 JUMBO .50 INCH DIGITS
ON ONE "STICK"!

(with colons and AM/PM indicator)

BOWMAR
4 DIGIT LED READOUT ARRAY
The Bowmar Opto-Stick. The best readout bargain we
have ever offered. Has four common cathode jumbo
digits with all segments and cathodes brought out.
Increased versatility since any of the digits may be used
independently to fit your applications. Perfect for any
clock chip, especially direct drive units like 50380 or
7010. Also use in freq. counters, DVM's, etc. For 12
or 24 hour format.

MICROPROCESSORS AND THINGS

8080A

By AMD. Outperforms INTEL

$24.00

8008-1

High Speed 8008

6.95

8212

I/O PORT nW COST

3.50

8224

Clock Generator \/AL^

4.95

8820

Dual Line RCVR HIGh

1.75

8830

Dual Line Driver

1.75

8838

Quad Bus Transceiver

2.00

MCI 488

RS232 to TTL

1.50

MCI 489

TTL to RS232

1.50

2513

Character Gen.

10.00

MM5204

4K E Prom

12.00

7400 —
7402 —
74L04
74S04 -
7404 —
7406 —
7408 —

7410 —

7411 —
7413 —
7420 —

19c
19c
— 29c
-44c
19c
29c
19c
19c
29c
50c
19c

TTL

7430

7432

7437

7438
7440

7447

7448
7451
7453

7473

7474
7575

INTEGRATED CIRCUITS

— 19c 7476 — 35c 74153 — 75c

7480 — 49c 74154 — 1.00

7483 — 95c 74157 — 75c

7485 — 95c 74161 — 95c

7586 — 45c 74164 — 1.10

7490 — 65c 74165 — 1.10

7492 — 75c 74174 — 95c

7495 — 75c 74181 — 2.50

7496 — 89c 74191 — 1.25

74121 — 38c 74192 — 1.25

74123 — 65c 74193 — 1.00

74141 — 75c 74195 — 69c

— 34c

— 39c

— 19c

— 85c

— 19c

— 39c

— 35c
-35c

$16.

Kit

JUMBO
LED
CAR
CLO CK

You requested it! Our first DC operated clock kit. Profession¬
ally engineered from scratch to be a DC operated clock. Not a
makeshift kluge as sold by others. Features: Bowmar 4 digit
.5 inch LED array, Mostek 50252 super clock chip, on board
precision time base, 12 or 24 hour real time format, perfect
for cars, boats, vans, etc. Kit contains PC Board and all other
parts needed (except case). 50,000 satisfied clock kit custo¬
mers cannot be wrong!

FOR ALARM OPTION ADD $1.50
FOR XFMR FOR AC OPERATION ADD $1.50

50 HZ CRYSTAL TIME BASE KIT - $6.95

All the featues of our 60HZ kit but has 50HZ output. For use
with clock chips like the 50252 that require 50HZ to give 24
hour time format.

UP YOUR COMPUTER!

21L02-1 IK LOW POWER 500 NS STATIC RAM
TIME IS OF THE ESSENCE

And so is power. Not only are our RAM's faster than a speeding
bullet but they are now very low power. We are pleased to offer
prime new 21L02 — 1 low power and super fast RAM's. Allows
you to STRETCH your power supply farther and at the same
time keep the wait light off. 8 for $12.95

1000 MFD FILTER
CAPS

Rated 35 WVDC. Up¬
right style with PC
leads. Most popular val¬
ue for hobbyists. Com¬
pare at up to $1.19
each from franchise
type electronic parts
stores.

S.D. Special
4 for $1 .00 _

60HZ CRYSTAL TIME BASE
2/$10. FOR DIGITAL CLOCKS __

S.D. SALES EXCLUSIVE! $5.95

KIT FEATURES:

A. 60hz output with accuracy comparable to a digital watch

B. Directly interfaces with all MOS Clock Chips

C. Super low power consumption (1.5 Ma typ.)

D. Uses latest MOS 17 stage divider 1C

E. Eliminates forever the problem of AC line glitches

F. Perfect for cars, boats, campers, or even for portable clocks
at ham field days.

G. Small size, can be used in existing enclosures.

KIT INCLUDES CRYSTAL, DIVIDER 1C, PC BOARD
PLUS ALL OTHER NECESSARY PARTS & SPECS.

SLIDE SWITCH
ASSORTMENT

Our best seller. Includes
miniature and standard
sizes, single and multi-
position units. All new,
first quality, name
brand. Try one package
and you’ll reorder
more. SPECIAL 1 2/$1 .

RESISTOR
ASSORTMENT

1/4 w 5% and 10%.
PC leads. A good mix
of values. 200/$2.

74S200

256 Bit High Speed RAM
Same as 82S16
$3.95

IK PROM BACK IN STOCK!
82S129. 256x4. Bipolar,
50NS,

FAST. WITH SPECS.

$3.95 _ _

FAIRCHILD BIG LED
READOUTS

A big .50 inch easy to read
character. Now available In
either common anode or
common cathode. Take your
pick. Super low current drain,
only 5MA per segment typical.
pNp — 510 Common Anode
FND — 503 Common Cathode
PRICE SLASHED! 59c each

TERMS:

Money Back Guarantee. No
COD. Texas Residents add 5%
tax. Add 5% of order for
postage and handling. Orders
under $10. add 75c. Foreign
orders: US Funds ONLY!

WESTERN DIGITAL UART

No. TR1602B. 40 pin DIP
This is a very powerful and
popular part.

NEW— $6.95 with data
LIMITED QUANTITY

C&K MINI TOGGLE SWITCH
No. 7103 SUB MINI SPDT
Center OFF.
SPECIAL -99c

MOTOROLA POWER
DARLINGTON

Back in Stock!

Like MJ3001. NPN 80V. 10A.
HFE 6000 TYP. TO— 3 case.
We Include a free 723 C volt
reg, with schematic for power
supply. SPECIAL -$1.99

SALE ON CUT LEAD
SEMICONDUCTORS

Leads were cut for PCB
Insertion. Still very useable.
All new, unused. Some House
no,

1N914/1N4148

100/$2.

1N4002 1 Amp 100 P|V
40/$ 1. #

1N4745A 16V 1W Zfener
20/$ 1.

EN2222 NPN Transistor
25/$l.

2N3392 GE Pre-amp Xstr
25/$l.

C103Y SCR. 800MA 60V
10/$1.

CALL YOUR BANK
AMERICARD OR MASTER
CHARGE ORDER IN ON
OUR CONTINENTAL

UNITED STATES TOLL
FREE WATTS:

1 -800—527-3460

Texas Residents Call Collect

214/271-0022

S.D. SALES CO.

P. O. BOX 28810 - D
Dallas. Texas 75228

DECEMBER 1976

CIRCLE NO. 56 ON FREE INFORMATION CARD

.13 7451 .17

.16 7453 .17

.15 7454 .17

.15 7460

.16 7464 -35

.19 7465 -35

.20 7470 -30

.20 7472 30

.18 7473

.19 7474

.16 7475 -49

.25 7476 JO

.43 7483 .68

.65 7485 .88

.35 7486 .40

.35 7489 2.25

.16 7490 .43

,30 7491 .75

.29 7492 .«

.27 7491 .48

.26 7494 .78

.29 7495 .79

.20 7496 .79

.23 74100 .98

.25 74105 .44

,25 74107 .37

.15 74121 .38

.89 74122 .38

.59 74123 .65

.73 74125 .54

.73 74126 J8

.73 74132 .89

.81 74141 1.04

.79 74145 1.04

.79 74150 .97

.17 74151 .79

74153 .89

74154 1.20

74155 .97

74156 .97

74157 .99

74158 1.79

74160 1.23

74161 .97

74162 1.39

74163 1.09

74164 .99

74165 .99

74166 1.25

74170 2.10

74173 1.49

74174 1.23

74175 .97

74176 .89

74171 .84

74180 .90

74181 2.45

74182 .79

74184 1.90

74185 2.20

74187 5.75

74190 1.15

74191 1.25

74192 .95

74193 .85

74194 1.25

74195 .74

74916 1.25

74197 .73

74198 1.73

74199 1.69

74200 5.45

CMOS

4000A

4001 A

400 2 A

4006A

4007 A

4008A

4009A

4010A

401 1 A

401 2A

4013A

4014A

4015A

4016A

4017A

.26 40 ISA

.25 4020A

.25 4021A

1.35 40 22 A

.26 4023A

1.52 4024A

.57 402SA

.54 4027 A

.29 4028A

.25 4030A

.45 403SA

1.Z7 4040 A

1.27 4042A

.48 404 S A

1,01 40S0A

1.39 4066A .89

1.72 4068A .44

1.18 4069A .44

.94 4071 A .26

.25 4072A J5

.89 4073A J9

.25 4075A .39

.59 4078A .39

.98 408 2 A .35

44 4518A 1-56

1.27 4529A 1.56

1.39 4585A 2.10

1.47
.59

MMS311 4.45

MM5312

MM S] 1* 4*45

MMS316 4.95
5375AA 4.95

CT70U1 5.95

CT5005
MM57 25
MM5736
MM 57*.
MMS739

NSL100

NSL101

NSL102

MVS020
RED .15

GREEN .15

AMBER .15

CtfAR .15

SPEAKER Enclosure Plans — Modern Design, Build Your¬
self. For Info Send Stamp. Eidson, Box 5046, Torrance,

Calif. 90503. _

ETCH IT YOURSELF PRINTED CIRCUIT KIT, Photo-Posi¬
tive Method — AH the supplies for four P.C. Boards, Direct
from magazine article in less than 2 hours. Only $19.95.
S.A.S.E. for details. Excel Circuits, 4412 Fern lee, Royal
Oak, Michigan 48073.

TAPE AND RECORDERS

RENT 4-Track open reel tapes— free brochure. Stereo-
Parti, P.O. Box 7, Fulton, pA 95401. _

HIGH FIDELITY

DIAMOND NEEDLES and Stereo Cartridges at Discount
prices for Shure, Pickering, Stanton, Empire, Grado and
ADC. Send for free catalog. LYLE CARTRIDGES, Dept. P,
Box 69, Kensington Station, Brooklyn, New York 11218.

1930-1962 Radio Programs. Reels, $1.00 Hour! Cassettes,
$1.00 Show!. . .Mammoth Catalog, $1.25. AM Treasures,
Box 192PE, Babylon, N.Y. 11702. _

SAVE 50% build your own speaker system write: McGee
Radio Electronics, 1901 McGee Street, Kansas City, Mis-
souri 64108. _

WANTED

RECORDS — TAPES! Discounts to 73%; all labels: no pur¬
chase obligations: newsletter; discount dividend certifi¬
cates; 100% guarantees. Free details. Discount Music
Club, 650 Main St., Dept 5-1276, New Rochelle, New York,
N.Y, 10801, _

GOVERNMENT SURPLUS

GOLD, Silver, Platinum, Mercury wanted. Highest prices
paid by refinery. Ores assayed. Free circular. Mercury
Terminal, Norwood, MA 02062.

MANUALS for Govt Surplus radios, test sets, scopes. List
50 cents (coin). Books, 7218 Roanne Drive, Washington,
P.C, 20021. _

GOVERNMENT SURPLUS. Buy in your area. How, Where.
Send $2.00. Surplus, 30177-PE Headquarters Building,
Washington, D.C. 20014.

TUBES

RADIO & T.V. Tubes — 36 cents each. Send for free
Catalog. Cornell, 4213 University, San Diego, Calif. 92105.

FREE KIT Catalog contains Test and Experimenter’s
Equipment. Dage Scientific Instruments, Box 1054P, Liver-
more, CA 94550.

SCIENCE supplies and kits, write for free catalog: Schubel
& Son, Box 214848-F, Sacramento, CA 95821.

TUBES receiving, factory boxed, low prices, free price list.
Transleteronlc, Inc., 1365 39th Street, Brooklyn, N.Y.
11 21 BA, Telephone: 212-633-2800. _

TUBES: "Oldies", Latest. Supplies, components, sche¬
matics. Catalog Free (stamp appreciated). Steinmetz, 7519-
PE Maplewood, Hammond, Ind. 46324.

REAL ESTATE

OPTO ISOLATORS

MCD2

Opto isolator diode

1.09

MCT2

Opto isolator transistor

.70

FREE CATALOG AVAILABLE ON REQUEST INCLUDES
RESISTORS £1% & +5%, TANTALUM CAPACITORS,
POWER SUPPLY KITS, CLOCK KIT5, TOOLS, RESIS-
rOR & CAPACITOR KITS & MISCELLANEOUS DEVI¬
CES

Dali incfuded with order on requesL
Add $.30 ea. it item is priced below $1.00

10% OFF WITH $25 ORDER
15% OFF WITH $100 ORDER

THESE DISCOUNTS APPLY TO TOTAL
OF ORDER - SPECIALS INCLUDED

DECEMBER SPECIALS

POCKIT CALCULATOR KIT

5 I got lion plus comtanl —
addressable memory with
individual retail — 9 drfri
dtspta, pi us overflow —
ballets u«fi — met standard
or tetharfleaWe baiieries — all
nerettais pjrit in read* 10
assemble Kym — instructions
HMluded

CMOS

4001 $ .19

4002 .20

4009 -39

4081 J9

74C00 .14

7403 .69

LINEAR

301 mDIP $ .22

733 TO-5 .79

739 DIP .79

741 mDIP .25

1458 mDIP .49

75150 DIP .95

Calc. KM. KM oo*r ...
AiReHef (aHuBne, dhp.)

MICROCPROCESSOR COMPONENTS

1101 256 BIT STATIC RAM 1.29

1103 1024 BIT DYNAMIC RAM .95

2102 1024 BIT STATIC RAM 1.49

S261 1024 BIT DYNAMIC RAM .95

F93410 256 BIT BI-POLAR RAM 1.39

1702A 2048 BIT PROM 9.95

TTL

7402

7410

7430

7438

7490

74193

AMAZING ELECTRONIC
Nk PRODUCTS yr'

LASERS SUPER POWERED, RIFLE, PISTOL POCKET SEE IN DARK • PYRO-
TECHNICAL DE BUGGING UNCRAMBLERS - GIANT TESLA • STUNWAND • TV
DISRUPTER • ENERGY PRODUCING, SCIENTIFIC DETECTION. ELECTRIFYING.
CHEMICAL ULTRASONIC, CB, AERO. AUTO AND MECH DEVICES. HUNDREDS
MORE - ALL NEW PLUS INFO UN LTD PARTS SERVICE.

INFORMATION luFtmctef

CATALOG $1 Bor 626 Lord JtHery PZ. • Amherst. N.H. 03031

UNiVBHSALBABADIOAPID

M*e» pijlrd copper {irtuil board
1-1/19“ * 1-1/ 18". 1 rows of r'
bo lei lor DIP IC's * spate lor
transistors. remlors 6 < apat ilort.
Versatile and simple lot brrad-
Jtojrdini 1C nrcuilry fl.BOoa.

74C74 1,04 74C162 2.49

74C76 1.34 74C163 2.66

74C107 1.13 74C164 2.66

74C1S1 2.62 74073 2.22

79054 J.1S 74095 2.26

79057 i.76 BOC95 1.15

74060 2.48 BOC97 .96

74061 2.49

Accommodate* S 14 ph IC'l with additional
interconnection hole*. 1/16“ phenolic wtlh diver
plated copper circuit*. 3 Vl4“ i 8 9/18" SI .80 •*-

CALCULATOR CHIPS CLOCK CHIPS

DISPLAYS

MAN1 $1.95
MAN2 3.9S
MAN3A .19
MANS 2.25
MAN6 2.49
MAN7 1.49
MANS 2.25
MAN66 2.25
D110A 2.19

FNDSOO 1.89
NS71L 1.39

DISCRETE LED'S

«« $ .29

FREECATALOGAVAILABLEON REQUEST

Satisfaction guaranteed. Shipment will be made postage prepaid within 3. days from
receipt of order. Payment may be made with personal check, charge card (include
number and eip. date), or money order. Phone Order* — BofA and M/C card or CO.D

Add $1.00 to cover shipping and handling if order is less than $10.00.

California resident! add sales ta*. Include shipping expense for orders shipped out of
U.S. and Canada appros. 10% of order.

INTERNATIONAL ELECTRONICS UNLIMITED

P.O. BOX 3036-R MONTEREY, CA. 93940 USA
PHONE (408) 659-3171

CIRCLE NO. 38 ON FREE INFORMATION CARD

BIG... NEW... FREE... SPRING 1977 CATALOG! Over
2,600 top values coast to coast! UNITED FARM AGENCY,
612-EP, West 47th, Kansas City, MO 64112.

RECORDS

RECORD RATERS WANTED! Anyone qualifies. We ship
you nationally released LP’s to rate. We pay postage and
handling. You pay nothing for LP's. All you pay is small
membership fee. Applicants accepted “first come basis."
Write: E.A.R.S., Inc., Dept PE, Box 10245, 5521 W. Center
Street, Milwaukee, Wisconsin 53210.

FREE. . . Fascinating NEW

XENON FLASH TUBE
Catalog . .

* H08BIESTS

* STUDENTS

* EXPERIMENTERS

BEACONS
PHOTO LAMPS
TEST

PHOTOLYSIS
SYSTEMS
> and more.

UNSURPASSED QUALITY
AND PRICES

CALL OR WRITE FQR YOUR
FREE ElEVAM CATALOG

TEC/WEST (U.S.A.) INC.

Kirkeby Center-Suite 1220 10889 Wilshire Btvd
Los Angeles, CA 90024 (213) 477-9529

CIRCLE NO. 74 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

ANNOUNCES THE

FAIRCHIU

SOLID STATE

TECHNOLOGY KIT

• FOR THE EXPERIMENTER WITH TASTE FOR "STATE OF THE ART" PRODUCTS

• COMPLETE SPECIFICATIONS ARE PRINTED ON THE BACK OF EACH TECHNOLOGY KIT

FTK0020

FTK0106

SOLID STATE

TECHNOLOGY
KIT

TECHNOLOGY BY

FAIRCHILD

TECHNOLOGY KIT

automobile clock

f=>=virc:mil-o

CARD FRONT

CARD BACK

CARD FRONT

DIGITS

FTK0001 0.5" High Common Cathode Digit

FTK0002 0.5" High Common Anode Digit

FTK0003 .357" High Common Cathode Digit

FTK0004 0.8" High Common Cathode Digit

FTK0005 0.8" High Common Anode Digit

0.8” HIGH DISPLAY ARRAYS

FTK0010 12 Hour, 3Y2 Digit Clock Display

FTK001 1 24 Hour, 4 Digit Clock Display

LED LAMPS

FTK0020 10 Red LED Lamps

FTK0021 5 Mixed Colored LED Lamps

FTK0022 1 0 LED Mounting Clips

FTK0023 5 Three Piece LED Mounting Adapters

PHOTO TRANSISTORS

FTK0030 5 Flat Lens Photo Transistors

FTK0031 5 Round Lens Photo Transistors

FTK0032 3 Flat Lens Photo Darlingtons

FTK0033 3 Round Lens Photo Darlingtons

PHOTO ARRAYS

FTK0040

9-Element Tape Reader Array

16.00

FTK0041

12-Element Card Reader Array

24.00

FTK0042

Reflective Opto Coupler

4.00

COUPLERS

FTK0050

3 General Purpose Opto Couplers

1.00

FTK0051

Darlington Opto Coupler

1.00

MOS CLOCK CIRCUITS

FTK0400

Digital Clock/Calendar Circuit

7.00

(FCM7001 )

FTK0401

Digital Clock/Calendar with BCD

7.00

Outputs (FCM7002)

FTK0402

Direct Drive Digital Clock Circuit

5.00

with AC Output (FCM3817A)

FTK0403

Direct Drive Digital Clock Circuit

5.00

with DC Output (FCM3817D)

FTK0405

Direct Drive Digital Clock/Calendar

6.00

Circuit (FCM7015)

KITS

FTK0106

Automobile Clock Kit

40.00

> THESE PRODUCTS ARE
PACKAGED FOR
OUTSTANDING WALL
DISPLAY APPEARANCE

Satisfaction Guaranteed. $5.00 Min. Order. U.S. Funds.

California Residents — Add 6% Sales Tax

Send a 24? Stamp (postage) for a Free 1977 Catalog

9 * mss

PRODUCT LINE
TO FOLLOW

1021 -A HOWARD AVE., SAN CARLOS, CA. 94070

PHONE ORDERS WELCOME — (415) 592-8097

i DEALER’S AND WHOLE¬
SALER’S INQUIRIES
INVITED — PRICE
LIST AVAILABLE.

► BUY WITH PRIDE THE
PRODUCTS BUILT BY
THE INDUSTRTS^^^^
LEADER -5ST55HTK5

DECEMBER 1976

CIRCLE NO. 41 ON FREE INFORMATION CARD

131

U.S. GOV’T ELECTRONIC SURPLUS

• Krtofltfr laewi - World tow SUtKUS CBHt* ottora
hut, ■oft CaitfMMMt SorjJa ilictridc uta mi

tif wiiti «t ■ fractfoa of tWr origU acqabMoa coat.

300-AMP., 200-VOLT RECTIFIER
• ( mil #11-1041 ) - - rout STAR SPKIAll WEST-
INGHOUSE, heavy duty unit. Excellent for use in 12 or
24-volt fast chargers, high current power supply systems,
etc. 3-5/8" x 1-3/8". 7/8" stud. ( 1 lb. )

$6.95 list Over $20.00

SNAP-AROUND VOLT-AMMETER /V

• (HIM #21-1021 )-- "NIHIPMH" clomp

type AC ammeter-voltmeter. Small enough to carry I wwj

in shirt pocket. Will measure 0 to 50-omperes, 0 \

to 250-volts. Furnished with test leads. Overall

size 4-1/2" x 2-3/4" x 1". ( 1 lb. ) U*t $31.00 $22 .95

STANDARD DIAL TELEPHONE

• ( ITEM #71$ ) - -Same os used on commer¬
ce] systems in U.S. A. Use as extension to private
system. Connect several together for local
intercom system. Instructions furnished.
$8.79 Original Cett $24.50 I 9 lbs. )

RUNNING TIME METER

• { HIM #2111 ) - - Record number of operating
hours of electric lights, electrical devices such as
refrigerators, furnaces, etc. Records total hours,
tenths and hundredths to 9,999.99 hours. For Co,t $*9.00
115-volts, 60-cydes. 4 Vi" x 3" x 21*". { 2 lbs. ) $4.39

SPECIAL SALE
Correspondence
Course In
ELECTRICAL
ENGINEERING

• ( HIM #9-111 ) - - Technical training at low cost! Lincoln
Engineering School suspended Correspondence Course because of
rising costs, limited number of Electrical Engineering Courses are
avoilable without exams and grading services. Consists of fifteen
lesson books, each with associated exams and standard answers.
Book showing how to build prize-winning Home Experimental
Laboratory Bench included at no extra cost.

All HEMS SHIPPED F.O.B. LINCOLN, NfBR.
Order Dkect Fran Ad - Seed For FREE Catalog

SURPLUS CENTER

DEPT. PE-126 UNCOIN, NiBR. 68501

]

DELTA

DELTA ELECTRONICS CO.

P.O. BOX 2, AMESBURY, MASS. 01913

SOLAR POWER FUN
The solar cells are both rated ar
430mV The larger cell is rated
at 500 mA, and the smaller cell
rated at 130mA. The smaller cell
will run the small motor and the
larger cell will run the larger motor
And also the larger cell will run
the smaller motor.

Large cell STK NO. PI 001 $8.95
Small cell STK NO. P5465 2.50

Larg mtr STK NO. P5456 3.95

Small mtr STK NO. P5457 2.50

If you buy the large motor and

cell together . 12.00

If you buy the small motor
and cell together . 4.50

LINCOLN CONTINENTAL RADIO
These are rugged solid state sets feati
mg push button tunning. And a hefty outu
stage. Built in fader control for front ai
rear speakers. 100% Guaranteed.

STOCK NO. P5443 $16.95 2/32.00

Send for latest free catalog. Minimum
order $5, phone orders welcome: (617)
388-4705. Include sufficient postage;
excess refunded. Bank AmeriCard 8t
Mastercharge welcome, ALL numbers
needed for processing. Min. charge $15.

132

CIRCLE NO. 20 ON FREE INFORMATION CARD

INSTRUCTION

LEARN ELECTRONIC ORGAN SERVICING at home all
makes including transistor. Experimental kit— trouble¬
shooting. Accredited NHSC, Free Booklet. NILES BRYANT
SCHOOL, 3631 Stockton, Dept. A, Sacramento, Calif.

95820. _

EARN ELECTRONICS DEGREE by correspondence. Free
information bulletin. Grantham, 2000 Stoner Avenue, Los
Angeles, California 90025. _ _

F.C.C.

EXAM

MANUAL

PASS FCC EXAMS! Memonie. study — ‘ Test

Answers" for FCC 1st end 2nd class Redio Tek-

. . , '£'*£7

ptrone licenses. Newly revised multiple etwice j /L i V***^*,
questions end diagrams cover alt areas tested in< jrf*,

FCC exams plus . SelLStudy Ability Test" 19. f]^

/r .'I-

postpaid. Moneyback Guarantee.

| command PRODUCTIONS P.O, BOX 26348-P
I note (Itiailtot timid SAN FRANCISCO, CALIF. 94126

SCORE high on F.C.C. Exams. . .Over 300 questions and
answers. Covers 3rd, 2nd, 1st and even Radar. Third and
Second Test, $14,50; First Class Test, $15,00. All tests,

$26.50. R.E.I., Inc., Box 806, Sarasota, Fla. 33577. _

UNIVERSITY DEGREES BY MAIL! Bachelors, Masters,
Ph.D’s. Free revealing details. Counseling, Box 317-PE12,

Tustin, California 92680. _

SELF-STUDY CB RADIO REPAIR COURSE. THERE’S
MONEY TO BE MADE REPAIRING CB RADIOS. This easy-
to-learn course can prepare you for a career In electronics
enabling you to earn as much as $16.00 an hour in your
spare time. For more information write: CB RADIO REPAIR
COURSE, Dept. PE126, 531 N. Ann Arbor, Oklahoma City,

Ok la. 73127. _

LEARN WHILE ASLEEP! HYPNOTIZE! Astonishing details,
strange catalog free! Autosuggestion, Box 24-ZD, Olympia,

Washington 9B507. _

GRANTHAM’S FCC LICENSE STUDY GUIDE — 377 pages,
1465 questions with answers/discussions — covering third,
second, first radiotelephone examinations. $10.70 post-
paid. GSE, 2000 Stoner, Los Angeles, California 90025.
INTENSIVE 5 week course for Broadcast Engineers. FCC
First Class license. Student rooms at the school. Radio
Engineering inc.,61 N. Pineapple Ave., Sarasota, FL 33577
and 2402 Tidewater Trail, Fredericksburg, VA 22401.
FREE Educational Electronics Catalog. Home study
courses. Write to: Edukits Workshop, Department 719D.

Hewlett, N,Y. 11S57. _

FCC License. New course material, new low prices. Free
home study catalog. Genn Tech, 5540 Hollywood Blvd.,

Hollywood, CA 90026. _

LEARN Computer Programming (BASIC and FORTRAN)
with ITI’s effective correspondence courses. Also Mathe¬
matics, Electronics (including FCC). Free Information: In¬
termountain Technical Institute, Box 258, Jerome, Idaho
B3338.

BUSINESS OPPORTUNITIES

I MADE $40,000.00 Year by Mailorder! Helped others make
money! Free Proof. Torrey, Box 318-NN, Ypsilanti,
Michigan 48197. _ _ _

FREE CATALOGS. Repair air conditioning, refrigeration.
Tools, supplies, full instructions. Dooiin, 2016 Canton,
Dallas, Texas 75201. _

MAILORDER MILLIONAIRE helps beginners make $500
weekly. Free report reveals secret plan! Executive (1K12),
333 North Michigan, Chicago 60601.

GET RICH with Secret Law that smashes debts and brings
you $500 to $5 Million cash. Free report! Credit 4K12, 333
North Michigan, Chicago 60601. _

PROFITABLE ONE-MAN

ELECTRONIC FACTORY

investment unnecessary, knowledge not required,
sales handled by professionals. Postcard brings
facts about this unusual opportunity. Write today!
Barta-DL, Box 246, Walnut Creek, CA 94597.

FREE SECRET BOOK ”2042 UNIQUE, Proven Enterprises”
Fabulous “Little Knowns". Work home! Haylings-B, Carls-
bad, Calif. 92008. _

HOW TO MAKE $2,000 WEEKLY at home using other
people’s money. Guaranteed. Free Details. Richlieu, Box

25277, Dept. F12, Houston 77005. _

BROADCAST STATION — FM or CABLE: excellent income,
free tapes-records. Free deteils. “Broadcasting,” Box
5516-AL, vyalnut Creek, CA 94596.

f PLANNING TO ^

Let us know 8 weeks in advance so that you
won't miss a single Issue of POPULAR
ELECTRONICS.

Attach old label where indicated and print
new address in space provided. Also include
your mailing label whenever you write con¬
cerning your subscription. It helps us serve
you promptly.

Write to: P.O. Box 2772, Boulder, CO 80323,
giving the following information:

□ Change address only □ Extend my subscription

ENTER NEW SUBSCRIPTION

□ 1 year $9.98 □ Payment enclosed

Allow 30-60 days for (1 extra BONUS issue)
delivery- □ Bill me later

NEW ADDRESS HERE 0191

Name _

Address.
City -

please print

State - Zip -

Additional postage per year: For Canada add S3. Fa countries outside
U.S. and Canada, add $5- cash in U S currency only

.—AFFIX QL^LABEL^ _ _

I l^oThTve no label handy, print OLD address here. ,

[_ Name' - please print J

) Address. - " ~

r _ I

I city - I

I State- - - - Zip _ 1

BOOKS AND MAGAZINES

FREE book prophet Elijah coming before Christ. Wonderful
bible evidence. Megiddo Mission, Dept. 64, 481 Thurston

Fid., Rochester, N.Y. 14619. _

POPULAR ELECTRONICS INDEXES For 1975 now avail¬
able. Prepared in cooperation with the Editors of “P/E,"
this index contains hundreds of references to product
tests, construction projects, circuit tips and theory and is
an essential companion to your magazine collection. 1975
Edition, $1 .50 per copy. 1972, 1973 and 1974 editions $1 .50
each, or $5.50 for the set of four (1972 thru 1975). Add $.25
per order for postage and handling. INDEX, Box 2228, Fatls
Church, Va. 22042. _

FREE CATALOG. Aviation and Space Books. Aero Pub¬
lishers, 329PE West Aviation, Fallbrook, California 92028.
THE AUDIO AMATEUR— A quarterly publication for the
serious audio constructor. Free prospectus. The Audio

Amateur, Box 176Z, Peterborough, N.H, 03458. _

MICROCOMPUTER Hobbyists - Dictionary of Micro¬
computer Terminology. Hundreds of definitions. For be¬
ginners and experienced. $2.00. Owen Products, Box
16116, Irvine, CA 92713. _ _

DISCOVER how liberty may soon become the exclusive
privilege of an elite few. Revealing 176 page hard-bound
book, “American Dilemma — Then and Now”. Please send
$5.95 payable to author, William Ingram, Box 758PE,
Roswell, GA 30077. _

CRIMEFIGHTERS, Debugging, Shoplifting, Lockpicking.
Free Information. Quimtronix, Box 548-PE, Seattle, Wash-
ington 98111, _

“UNUSUAL" BOOKS! 40 for $5! 5 lb. GraBag $6. Free
Catalog! International, Box 7798PE, Atlanta, GA 30357.

HYPNOTISM

SLEEP learning. Hypnotic method. 92% effective. Details
free. ASR Foundation, Box 23429EG, Fort Lauderdale,

Florida 33307, _

FREE Hypnotism. Self-Hypnosis. Sleep Learning Catalog!

Drawer H400, Ruidoso, New Mexico 88345. _

AMAZING self-hypnosis record releases fantastic mental
power. Instant results! Free trial. Write: Forum (AA12), 333
North Michigan, Chicago 60601.

POPULAR ELECTRONICS

SOLVE YOUR TEST CONNECTION PROBLEMS

E-Z Hooks have been designed and field tested throughout the industry to save time and money in commercial
■ Aff I electronic production and servicing. The spring-loaded hook attaches firmly, yet so gently it will not damage com-

■Rb I ■ Vf JK, ponent — frees hands while testing. Durably constructed and fully insulated to a single contact point assuring true

" ™ " m mm IBm ■ II readings. Meets exacting laboratory and space age computer technology requirements. AVAILABLE IN 10 RETMA

COLORS: Red, black, blue, green, orange, yellow, white, violet, brown or gray.

EXTRA LONG
MINI HOOK

XL*1 Mini Hook (5.0" long! combines all the proven features of the X100W with an extra long body. It
Mill niaka lafa, short -free test connections in card rack* and through deep Miring nest up to 4**.$1.25 ea.

JUMPER WITH
XL-1 MINI HOOKS

Jumper. XM Micro Hook to Banane Plug
Order No. Length Price
201 XM* 32" SI .40 Specify color.

X100W Mini Hook {2.25" long! combines -
rugged construction, miniature size and
Finger-eze Hypo Action for all the best
test connections. Hook is large enough
for component leads, yet small enough

to get into tight places . $.75 ea.

Specify color. ORDER X100W

Jumper X-100W Mini Hook**
to Stacking Banana Plug
Order No. Length Price

201 W* 32" $1.35 Specify color.

Order No. Length Price ^

204XL1-12 12" 52.60

204XL1-24 24" 2.60 Specify color.

JUMPER, XL-1 MINI HOOK TO STACKING

BANANA PLUG Order No. Length Price

201 XL-1* 32" $155 5Pe

COMPLETE SET $7.95

ORDER YOUR XM-S MICRO HOOK SET TODAY! (Includes 1 ea. red, black, blue, green,
orange, yellow, white, brown, violet and gray Micro Hook) At this low price you can afford
more than one set.

CONTINENTAL SPECIALTIES

^ PROTO BOARDS

Build & test circuits as fast as you think f ”

6 1C cap breadboard kit

10 1C cep breadboard kit

10 14 -DIP cap, 5-way post, 940 eofderlan
tie points, 6.8 x 4.5"

12 14-DIP cep., like PB101 with 1,240 tie
point*, 7.0 x 4.5"

24 14-DIP cap., 4 5-way porn, 2,250 tie
point*, 6.0 x 9.0"

32 14-DIP cap., 3,060 lolderle** tie points,
8.0 x 9.76"

LOGIC MONITOR 1

LOGIC MONITOR 2

Simultaneously display* static^ 5 El Display* *tatic end dynamic
vtd dynamic logic statei of la El *tate* of digital 1C* such as C
OTL, TTL, HTL or CMOS 83 E j MOS, HTL, TTL, DTL 8. RT L.
DIP 1C* Pocket size. $74.95 5 n T* Selectable threshold control.

$124.95

LOGIC PROBE LP-1

Compact, circuit -powered multifunction logic probe. Mufti family
compatibility. DTL/TTL/HTL/CMOS. Traces logic levels and pulses
through digital circuitry. $44-95.

For power-on/handi off

PROTO-CLIP

signal tracing. Bring 1 C leads up 1

from PC board surface for fast trouble-shooting.

PC14

14-pin $4.60 B

PC16

16-pin 4,75 l

PC24

24 pin 8.60

SOCKETS & BUS STRIPS

— — —5 la Plug-in, wire, test, modify or expand without patch cords

I=E “ D or solder. Snap together to form breadboard needed.

j H PN/Description Ttrm'h Price

S! H QT59S Socket 118 $12.50

— :-Rsl OT59B Bus 20 2.60

i-:i: I®? I QT47S Socket 94 10.00

HHi * OT47B Bu» 16 2.25

•Hi: :••:: J " QT35S Socket 70 8.50

••HI si::: » H QT35B Bus 12 2.00

i;lii I!!!! * QT1BS Socket 36 4.75

i::i: Hi:: H QT12S Socket 24 3.76

« j « J<*J QT8S Socket 16 3.25

QT7S Socket 14 3.00

PROTO BOARDS

With built in regulated short-proof power supplies
PB203 5V, 1 amp regulated power supply $ 75.00

PB203A 5 V, 1 amp and ±15V, >4 amp regulated 120.00

power supply

DESIGN MATES

DESIGN MATE 1 . CIRCUIT DESIGNER

With built-in, regulated, metered power supply to
design unusual circuits fast. ......... $54.95

DESIGN MATE 2. . . FUNCTION GENERATOR
Complements Design Mate 1. Produces cleon, ac¬
curate wove forms with variable amplitude and frequency controls.
569.95

DESIGN MATE 3 . . . .R/C BRIDGE

Saves design time by measuring end selecting capacitors and resistors

to better than 5% instantly! . . . $59.95

DESIGN MATE 4 . MULTIPURPOSE PULSE GENERATOR

With the precision and versatility of a laboratory instrument, ideal
wherever a source of clean, fast output pulses compatible with
virtually all logic families and discrete circuits is needed . . .$124.95

BREADBOARD JUMPER WIRE KIT

Each kit contains 350 wires cut to 14
different lengths from 0.1" to 5.0*.
Each wire is stripped and leads are
bBnt 90° for easy insertion. Wire
length is classified by color coding,
■g’ ft»55S5SS All wire is solid tinned 22 gauge with

-■ m j* PVC insulation. The wires come

'J1 packed in e convenient plastic box.

BK-! . $9.95

CARBON FILM RESISTORS (5%)
Only in Multiples of
100 pcs per value (ohms)
XW... $1.69 per 100
XW ... $1 .79 per 100

10 100 1.0K 10K 100K 1.0M

11 110 1.1 K 1 1 K 1 10K 1 .1 M

12 120 1.2K 12K 1 20K 1.2M

13 130 1.3K 13K 130K 1.3M

15 150 1.5K 1 6K 150K 1.5M

16 160 1.6K 16K 160K 1.6M

18 180 1.8K 18K 180K I BM

20 200 2.0K 20K 200K 2.0M

22 220 2.2K 22K 220K 2.2M

24 240 2.4K 24K 240K 2-4M

27 270 2.7K 27K 270K 2.7M

30 300 3. OK 30K 300K 3.0M

33 330 3.3K 33K 330K 3.3M

36 360 3.6K 36K 360K 3.6M

39 390 3.9K 39K 390K 3.9M

43 430 4.3K 43K 430K 4.3M

47 470 4.7K 47K 470K 4.7M

51 B10 5.1 K 51 K 51 OK 5.1M

56 560 5.6K 66 K 560K 6.6M
62 620 6.2K 62K 620K 6.2M
68 680 6.8 K 68K 680K 6.8M
75 750 7.5K 76K 750K 7.5M
82 820 8.2 K 82K 820K 8.2M
91 910 9. IK 9 1 K 91 OK 9.1M

RESISTOR ASSORTMENTS

Each assortment contains 5 pcs each of 1 0 different values.
Values included ere shown in (Ohms)

XW.5% (50 pcs total) .. .51.75
XW. 5% {50 pcs total) ... SI .85

Asst. 1:10, 12. 15, IB. 22, 27. 33. 39. 47. 56 ohm

Asst. 2:68. 82, 100, 120, 150, 180. 220. 270, 330, 390 ohm
Asst. 3: 470, 560, 680. 820 ohm, IK, 1.2K, 1.5K. 1.0K. 2.2K, 2.7K
Asst. 4: 3.3K, 3.9K, 4.7K,. 5.6K, 6.8K, B.2K.10K. 12K, 15K, 18K
Asst. 5: 22K, 27K. 33K, 39K, 47K, 56K. 68K. 82K. 100K, 120K
Asst. 6: 150K, 180K , 220K. 2 70K, 330K, 390K, 470K. 560K. 680K.
820K

Asst. 7: 1 M, 1.2M, 1.5M, 1.8M, 2.2M.2.7M, 3.3M, 3.9M, 4.7M, 5.6M
Asst 8R:{ Alt seven assortment* above)

MW. 5%, 350 pcs total: S10.95-MW. 5%. 350 pci total: 51 1 .55

(RADIAL LEAD)

MFD

10V16V2SV 35V 50V

.12 .13

.14

.15

.16

.13 .14

.17

.20

.24

.14 .15

.18

.22

.26

.15 .16

.21

.23

.28

.16 .17

.22

.24

.30

.17 .18

.24

.25

.32

100

.18 .20

.26

.30

.35

220

.23 .25

.35

.40

.60

330

.30 .33

.40

.45

.55

470

.36 .40

.45

.60

.80

1000

_ _

.65

.80

1.20

2200

—

1.30

1.60 2.50

MATSUO

DIPPED

TANTALUM

CAPACITORS

$ MF V S

.33 6.8 16 .40

.33 6.8 35 .45

.33 10.0 16 .42

.33 10.0 25 .45

.33 10.0 35 90

.33 15,0 20 .45

.33 15.0 36 1.32

PLESSEY

POLYESTER

[CAPACITOR)

MF V $
.001 1000 -14

.0012 1000 .14
.0015 1000 .14
.0018 1000 .14
.0022 1000 .14
.0027 1000 .14
.0033 1000 .14
.0039 630 .14

.0047 630 .14

.0056 630 .14

.0068 630 .14

.0082 630 .14

.01 630 .14

.012 630 .14

.016 400 .15

.018 400 .15

.022 400 .15

,027 400 .15

.033 250 .15

MINI BOX
MF V $
.039 260 .15
.047 260 .16
.056 250 .16
.068 250 .15
.082 250 .17
.1 100 .17

.12 100 .18
.16 100 .20
.18 100 .21
.22 100 .23

.27 100 .26

.33 100 .30

.39 100 .33

.47 100 .36

.56 100 .44

.68 100 .47

.82 100 .54

1.0 100 .60

DECEMBER SPECIALS

- ONLY ONE ORDER PER CUSTOMER -

PCS

P*r

per

pkg

SIGNETICS

pkg

FAIRCHILD

Pkg

4000AE

.90

7406N

1.90

4002 A E

1.30

7420N

1.40

4007 A E

1.70

TEXAS INSTRUMENTS

401 1 AE

1.80

7425N

2.50

4012AE

1.70

7437N

2.20

4013AE

3.80

7438N

2.20

100

401 3AE

34.50

NSC

4025AE

1.70

7440N

1.40

4027 AE

4.30

FAIRCHILD

100

4027AE

38.50

7483N

6.70

4030 A E

3.80

7486N

3.10

4049AE

3.80

NSC

100

4049 A E

34.10

74157N

6.30

4050AE

3.80

EXAR

100

4050AE

34.10

XR567CN

16.00

451 0AE

9.90

100

XR567CN

140.00

Valid only until December 31.

. 1976

7400 .18

7401 .20

7402 .18

7403 .20

7404 .21

7405 .23

7406 .30

7407 .36

7408 .28

7409 .28

7410 .22

7411 .25

7412 ,36

7413 .64

7414 .98

7416 .42

7417 .42

7420 .15

7421 .38

7422 .60

7423 .35

7425 .40

7426 .30

7427 .36

7428 .50
7430 .26

7400N TTL

7432 .32 7480 .80

7433 .44 7482 1.50

7437 .36 7483 .82

7438 .36 7485 1.20

7439 .36 7486 44

7440 .20 7489 2.20

7441 .90 7490 .56

7442 -66 7492 .60

7443 .78 7493 .62

7444 1.05 7494 .88

7445 1.06. 7495 .90

7445 1 .05 7496 .80

7447 .98 7497 5.00

7448 .98 74100 1.20

7450 .15 74105 .90

7451 .16 74107 .40

7453 .18 7 4109 .45

7454 .18 74110 .80

7459 .25 74111 1.00

7460 .19 74116 2.00
7470 .40 74118 2.00

7472 .40 74121 .60

7473 .42 74122 .48

7474 .42 74123 .95

7475 .70 74125 .55

7476 .44 74126 .60

74147 2.00 74180 1.20 1

74148 1.80 74181 3.10

74152 1.20 74185 2.90

74153 1.20 74188 5.00

74154 1.20 74190 1.40

74155 1.10 74191 1.30

74156 1.20 74192 1.20

74157 1.20 74193 1.20

74158 1.40 74194 1.20

74160 1.30 74195 1.00

74165 1.60

74166 1.60
74170 2.00

74173 1.70

74174 1.20

74200 7.00
74221 1.40
74279 1.20
74298 1.80

WAVEFORM
GENERATOR KIT
EXAR XR205K

1 5 I £30 95 Here’s a highly versatile lab instru-
10 1 ment at a fraction of the cost of

r, q , - - — conventional unit.

| _ iMfcl ''ftm Kit includes 2 XR

6 I 205 ICs, data and

4 I applications, a PC

3 I $50.40 board (etched and

drilled, reedy for
assembly) and de
tailed instructions.

4000AE .2

4001 AE .2
4002 A E .2
4006AE 1.3
4007AE .2

4008AE 1.4
4009AE .5

4010AE .5

401 1AE .2
4012AE .2

4013AE .4

4014AE 1.2
401 5 AE 1.3
401 6AE .E

401 7AE 1.1

4018AE 1.2
4019AE .£

402 0AE 1.4
4021 AE 1.:
4022AE 1.(

HIGH SPEED TTL

.33 74H08N ,40 74H73N ,B0

.33 74H 1 0N .33 74H74N .80

74LSOO

.36 74LS32N .45 74LS112N .58

.36 74LS51N .39 74LS114N .92

.44 74LS54N .58 74LS138N1.89

.45 74LS73N .58 74LS139N2.00

.38 74LS74N .56 74 LSI 51 N 1 .68

.36 74LS76N .65 74L5153N1.80

.44 74LS107N .59 74LS16PN3.00
.39 74 LSI 09N .92 74LS161N3.00
SCHOTTKY TTL

.44 74S11 .65 74S64 .80

.60 74S20 .65 74S74 .90

.55 74S30 .80 74S76 1.15

.80 74S32 .80 74S112 1.00

.55 74S40 .65 74S113 1.50

CMOS

.20 4023AE .24 4051AE 1.70

4024AE .95

4025AE .24

4026AE 2.50
4027AE .55

4028 A E 1.00
4029AE 1.20
4030AE .46

4033AE 2.00
4035AE 1.30
4040AE 1.20
4041 A E 1.25
4042 AE 1.20

4052 A E 1 40
-4053AE 1.70
4055AE 1.95
4056AE 1.99
4060AE 2.10
4063AE 2,50
4066AE .90

4068 A E .44
4069AE .44

4070BE .50

4071 AE .45
4072AE .34

4043AE .95 4073AE .40
4044AE 1.10 4075AE .40

4046AE 3.10
4047AE 2.50
4048 AE 1.43
4049AE .58

4050AE .58

4075 AE 1.24
4077AE .40

4078AE .40

4081 BE .40

4082 AE .39

74LS1 74N2.20
74LS1 75N2.40
74LS181N3.69
74LS19ON2.05
74LS191N2.85
74LS193N2.50
74LS260AJ .44

74S114 1.20

74S133 .80

74S138 2.20

74S151 2.20

74S160 3.90

74S257 2.40

4093AE 1.65
4095BE 1.95
4098 A E 2.50
4099AE 2.90
4502AE 1.50
4607BE .60

4508BE 2.20
4510AE 1.40
451 1 BE 1.30
4512BE 1.30
4514AE 5.00
4515AE 5.00
4516AE 1.75
4618AE 1.50
4520AE 1.28
4528AE 2.20
4585AE 2.05
4901 AE .32
491 1AE .32

PLESSEY SAMPLER

300 METALIZED CAPACITORS eoc f|fi
18 DIFFERENT STD. VALUES 3,ZOlUU

L-15 PULSE/SWEEP FUNCTION GENERATOR KIT

_ _ _ FEATURES: 1 HZ to 1 00 K Hz in 5 ranges, at con

“““ stant amplitude - Sine and triangle adjustable to
■ 0 f j 20vp-p into 600 Ohms * Sine distortion is .5%
typical • Voltage controlled sweep of sine and tri-

— - - angle waves - TTL square wave has a fully adjustable

pulse and drives 600 ohms • Frequencies of lower
than 1 Hz end greeter than 100 kHz are obtainable • short proof
Complete with power supply and metel case . S55.00

DECEMBER 1976

Minimum order $10.00. Add $1.00 to cover postage and handling.
California residents add 6% sales tax. Mail Ordar — Send Check or
money order to: P.O. Box Z208P, Culver City, CA 90230 • Phone
Order - Call: (213) 641-4064. COD, Master Charge and Bank-
Americard welcomed. (Stores do not accept mail or phone orders.)

CALIFORNIA

ANCRONA

CALIFORNIA

ANCRONA

1 1080 Jefferson Blvd. 1300 E. Edinger Ave.
Culver City, C A 90230 Santa Ana, CA 92705

(213) 390-3595

(714) 547-8424

ARIZONA
ANCRONA
4518 E. Broadway
Tucson. AZ 85711
(602) 881-2348

OREGON GEORGIA CANADA. B.C.

ANCRONA ANCRONA ANCRONA

1125 N.E. 82nd Ave. 3330 Piedmont Rd. NE 5656 Fraser St.
Portland, OR 97220 Atlanta, GA 30305 Vancouver, 8C V5W2Z4
(503)254-5541 (404)261-7100 (604)324-0505

CIRCLE NO. 9 ON FREE INFORMATION CARD

SIUIT ELECTICIKS

P.O. BOX 19442P • DALLAS, TEXAS 75219 * 214/823-3240

PS-01 POWER SUPPLY KIT

IMAGINE! A power supply with a well filtered, regulated
output in three voltages. The PS-01A has quality 1C regulators,
semiconductors and components. The transformer is custom
designed and well made. Features lOmv load regulation.

YOU GET:

Drilled end Plated board jm f

Complete kit of components ^ I wM U

Heatsinks +5V & 1.SA

Complete Instructions +15V 9 200 MA

NOTE: +6 and ±12VDC supply is available at same

_ price. Order PS-01/B. _

BUILD A COMPLETE CDI IGNITION KIT AT A FRACTION
OF THE COST OF OTHER UNITS. A special buy allows us to
sell the complete kit at this low price! Up to 40,000 volts from
your present ignition without changing the coil. Simple
connections.

INCLUDES: Special toroid transformer

Drilled and Plated board y

Complete instructions Wfl U

All resistors and caps m

All semiconductors

(Does not include heatsink or casa.) For 12V negative ground
systems. _ _

$9.95

QUALITY METAL PROJECT CASES

2 7/8" x 2K" x 1»" $1.60

414" x 2%" x 1 7/8" 2.15
SHADOW FRONT
4 13/16" X 3K" x 2” 3.50
7" X 4" X 2 3/8" 4.35

BA2O0V Guaranteed! UNVM°AL™ECDE cooo

— ^ | 7509 P-iv R«9 50c

.as V-

Can bo uveo wim a>i«mai p*i\ tronUttor

UNMARKED - TESTED GOODrm ,>t,h cu,,cr11 Guaranteed'

UIT1AS0NIG SENIEH-HEGEIVtH KIT

A special buy on a high quality ultrasonic transducer allows us to offer
this kit at a super price - but hurry, quantities are limited I You can
build intrusion alarms, motion datectors, remote controls, echo ranging
or liquid levtl measurement equipment. We supply the basic transmitter
and receiver electronics including a drilled and plated PC board. The units
work at 23KHZ with a range of 20 ft. and can be positioned opposite
each other or slde-by-side and bounced off a solid surface. The output
will sink up to 300ma to drive a relay, alarm circuit, etc.

ORDER US-01 _ S19.95

HTML* mm Kit A piercing tO WATTS of duel tone no.** that
can't t» ignorad. Perfect tor burglar elrnimt. werning denen. or to call your kid*

CIRCLE NO. 14 ON FREE INFORMATION CARO

CLASSIFIED ADVERTISING ORDER FORM

Please refer to heading on first page of this section for complete data concerning terms, frequency discounts, closing dates, etc.

31 32 33 34 35

WORD COUNT: 15 WORD MINIMUM. Include name and address. Name of city (Des Moines) or of state (New York) counts as one word each. Zip
Code numbers not counted. (Publisher reserves right to omit Zip Code if space does not permit.) Count each abbreviation, initial, single figure or
group of figures or letters as a word. Symbols such as 35mm. COD, PO, AC. etc., count as one word. Hyphenated words count as two words. Tele¬
phone numbers count as one word. rrr-ri

_ Words $2.25 (Commercial Rate) $1.35 (Reader Rate)

D Payment of $ _ enclosed for - insertion(s). pPfl&l

CHARGE: Q American Express D BankAmericard D Master Charge D Diners Club' -

for _ insertion(s). You will be billed monthly.

Account # _ _ Expiration Date -

Master Charge Interbank # (4 digits above name) -

SIGNATURE MUST BE PROVIDED BELOW

PRINT NAME - _ _ _

EMPLOYMENT OPPORTUNITIES

PERSONALS

ELECTRONICS/AVIONICS EMPLOYMENT OPPORTUN- _

ITIES. Report on jobs now open. Details FREE. Aviation MAKE FRIENDS WORLDWIDE through international
Employment Information Service, Box 240E, Northport, correspondence. Illustrated brochure free. Hermes-Verlag,
New York 11768. Box 110660/Z, D-1000 Berlin 11, Germany.

2522 STAT SR .

. > . S2.75

INTEL 8080 CPU .

. . S24.50

2518-HEX 32 BIT SR ... .

. . . $5.00

2102-1 1024 BT RAM .

. . SI. 80

5280-4 K DYNAMIC RAM . .

. . , S12.50

5202A UV PROM .

, , , SI 2.50

MM5203 UV PROM. .

, . SI 2.50

1702A UV PROM ......

SI 0.75

5204 -4 K PROM .

, . . $24.95

MINIATURE MULTI-TURN

TRIM POTS

100. 500, 2K, 5K, 10K, 100K. 200K

$.75 each .

. . . .3/S2.00

LIGHT ACTIVATED ScFVs

TO-18. 200V 1 A .

. . . . S 1.75

TRANSISTOR SPECIALS

2N3585 NPN Si TO-66 ....

, , , . $ .95

2N3772 NPN SITO-3 ....

. . . $ 1.60

2N4908 PNP Si TO-3 ....

. . . S 1.00

2N6056 NPN Si TO-3 Darlington . S 1.70

2N 5086 PNP Si TO-92 ....

. .4/S 1.00

2N4898 PNP TO-66. ....

, . S .60

2N404 PNP GE TO-5 ....

. 5/$ 1.00

2N3919 NPN Si TO-3 RF ..

... S 1.50

MPSA 13 NPN S. TO-92 . .

. . 3/$ 1 .00

2N3767 NPN Si TO-66 ....

... $ .70

2N2222 NPN Si TO-18 ....

. . 5/$ 1 .00

2N3055 NPN Si TO-3 ....

. S .80

2N3904 NPN Si TO-92 ....

, 5/S 1 .00

2N3906 PNP Si TO-92 ....

, . 5/S 1.00

2N5296 NPN Si TO-220 . . .

. S .50

2N6109 PNP Si TO-220. . . .

... $ .55

2N3638 PNP Si TO-5 ....

. . 5/S 1 .00

2N651 7 NPN TO-92 Si ... .

. , 3/S 1 .00

C/MOS (DIODE CLAMPED)

74C02- .22 4015- .95

4035-1.10

74C10- .22 4016- .40

4042- .78

4001- .22 4017-1.05

4047-2.00

4002- .22 4018-1.00

4049- .40

4006-1.20 4019- .22

4050- .40

4007- .22 4022- .95

4066- .80

4009- .42 4027- .40

4071- .22

4010- .42 4028- .88

4076- .70

4011- .22 4029-1.10

4081- .22

4012- .22 4030- .22

4520-1.15

4013- .40

LED READOUTS

FND 500-.5” C.C. . .

SI. 95

HP 7740-.3" C.C .

. . . . $1.40

MAN-7-.3" C.A. ...

. SI .25

NS 33-3 dig. array ......

. SI .35

DL 747 .

Send 25dfor our catalog featuring

Transistors and Rectifiers

145 Hampshire St., Cambridge, Mass.

PRINTED CIRCUIT BOARD

TANTULUM CAPACITORS

4 1 2" x6 1 ? ' SINGLE SIDFD Ff’OXY

BOARD IMG" k. imntchnil

5.50 ea .

, 5/S2.20

VECTOR BOARD 1" SPACING
4.5" x 6" SHEET .

. $1.25

7 WATT LD-65 LASER DIODE SS95

.22UF 35V 5/S 1.00

4.7UF 35 V 4 /SI. 00

.47UF 35V 5/S1.00

6.8UF 35V 3/SI. 00

.6BUF35V 5/SI .00

22UF 35V

S .40

1UF35V 5/SI .00

33UF 35V

$ .40

2.2UF 20V 5/SI . 00

30UF 6V

5/SI .00

3.3UF 35V 4/SL 00

100UF 35V

S .50

2N 3820 P FET .

. S .45

2N 5^57 N FET .

. S .45

2N4891 UJT . . .

. S .45

TIS43UJT .

_ S .35

ER 900 TRIGGER DIODES.

- 4/SI .00

2N 6020 PROG. UJT ...

. S .65

VERIPAX PC BOARD

This board is a 1/16" single sided paper epoxy

board, 4%”x6’4" DRILLED

and ETCHED

which will hold up io 21 single 14 pin IC's
or 8, 16, or LSI DIP IC's with busses for
power supply connecior . S4.00

MV 5691 YELLOW-GREEN

BIPOLAR LED .

. , , , SI. 25

FP 100 PHOTO TRANS . . .
RED, YELLOW, GREEN OR

. S .50

AMBER LARGE LED's

. . . ea. S .20

14 PIN DIP SOCKETS _

. S .25

16 PIN DIP SOCKETS . . , ,

MOLEX PINS .

. . 100/SI. 00

1 000/ S 7.50

8 PIN MINI DIPSOCKETS .

. s .25

10 WATT ZENERS 3.9, 4.7, 5.6. 8.2, 12, 15.

18, 22, 100, 150 or 200V

- - - ea. S.60

1 WATT ZENERS 4.7, 5.6, 10

18 OR 22 V

. , aa. S .25

NATIONAL

MM1402 1.75
MM1403 1.75
MM1404- 1.75
MM5013- 2.50
MM5016- 2.50
MM5017- 2.70
MM5Q55- 2.25
MM5056- 2.25

MOS DEVICES

MM50S7- 2.25
MM5058- 2.75
MM 50 60 - 2.75
MM5061 - 2.50
MM5555- 4.75
MM5556- 4.75
MM5210- 1.95
MM5260- 1.75

Silicon Power Rectifiers

Terms: FOB Cambridge, Mass.
Sand Check or Money Order,
include Postage, Minimum
Order *5.00, COO’S $20.00

SILICON SOLAR CELLS

2%" diameter

.4V at 500 ma _ $5.00 ea., 6/$27.50

REGULATED MODULAR
POWER SUPPLIES

+ — 1 5 VDC AT lOOma

115VAC INPUT . . . S27.95

5VDC AT 1 A 11 5VAC INPUT . . . S24.95

12 VDC AT ,b AMP . $24.95

IN 4148 t i N9 1 4l . 15/SI .00

7400-

.14

7442-

.52

74125-

.40

7401-

.14

7445-

.70

74126-

.40

7402-

.14

7446-

.70

74151-

.70

7403-

.14

7447-

.70

74153-

.65

7404-

.18

7448-

.70

74154-

1.10

7405-

.18

7450-

.20

74155-

.70

7406-

.20

7472-

.30

74157-

.70

7407-

.25

7473-

.30

74161-

.85

7408-

.21

7474-

.30

74164-

.96

7409-

.21

74 75-

.49

74165-

1.05

7410-

.15

7476-

.35

741 73-

1.40

7411-

.20

7480-

.35

74174-

.95

7412-

.20

7483-

.70

74175-

.92

7413-

.45

7485-

.88

74177-

.79

7414-

.70

7486-

.30

74188-

.70

7416-

.25

7489-

1.85

74181-

2.10

7417-

.25

7490-

.45

74 1 go-

1.20

7420-

.20

7491-

.70

74191 -

1.20

7425-

.28

7492-

.50

74192-

-85

7420-

.25

7493-

.45

74193-

.85

7427-

.30

7494-

.70

74194-

.85

74 30-

.20

7495-

.70

74195-

.75

7432-

.25

7496-

.70

74196-

.88

7437-

.25

74107-

.32

75324-

1.75

7438-

.25

74121-

.35

75491-

.65

7440-

.16

74123-

.65

75492-

.65

7441-

.85

MINIATURE DIP SWITCHES
CTS-206-4 Four SPST switches

in one mtnidip package. . , SI. 75
CTS- 206-8 Eight SPST switches in a 16
pin DIP package . S2.85

AY-5-101 3-A30K ser./par., par./s er., uni¬
versal UART. * . S6 95

ALCO MINIATURE TOGGLE SWITCHES

MTA 106 SPDT . . . SI .20

MTA 206 DPDT . SI .70

Full Wave Bridges

■ PR V 2A 6A

25A

I 200 .95 1.25

2.00

400 1.15 1.50

3.00

| 600 1.35 1.75

4 00 1

SANKEN AUDIO POWER AMPS fl

Si 1010 G 10 WATTS . . . .

S 6.90 1

| Si 1020 G 20 WATTS, , . .

SI 3.95 |

1 S. 1050 G 50 WATTS .

S24.95 |

CCD 110 LINEAR 256 XI BIT SELF 1

SCANNING CHARGED COUPLED

DEVICE . S99.00 I

CCD 201 100 x 100 CHARGE

COUPLED DEVICE .

SI 35 00

LINEAR CIRCUITS

LM307 -Od. Amp .

S .30

LM 309 K 5V 1 A REGULATOR .

SI. 15

723 - 40 + 4QVV RFGULATOR .

S .50

301/748-Hi Per. Op. Amp .

S .31

320T 5,12,15. or 24V NEG REG .

SI. 50

709C Op, Amo .

$ .31

741 A or 741COPAMP .

S .31

710 COMPARATOR .

$ .35

CA 3047 Hi Pef. Op. Amp .

.$ 95

340T 5, 6, 8. 12, 1 5, 18, 24V POS

REG. TO-220 .

SI .50

101 OPER. AMP. HI PERFORM. .

S 75

LM 308 Oper. Amp.. Low Power .

S .95 ■

747 -DUAL 741 .

S .65

556- DUAL TIMER .

S1.00

537 - PRECISION OP. AMP. . . .

SI 70

LM 3900 — OUAD OP AMP . . .

S .49

LM 324 -QUAD 741 . .

SI. 50

560 - PHASE LOCK LOOP

S2.00

561 - PHASE LOCK LOOP . . ,

S2.00

56$ - PHASE LOCK LOOP . . .

' SI. 25

566 FUNCTION GEN .

SI .65

567 -TONE DECODER .

SI .50

LM 1 31 ON FM STEREO DEMOD.

S2.75

8038 1C VOLTAGE CONT. OSC.

S3 .90

LM 370 - AGC SOUELCH AMP.

SI. 15

555 -2>iS-2 HR. TIMER .

S .45

553 OUAD TIMER .

S2.50

FCD 810 OPTO- ISOLATOR . . .

S .80

1458 DUAL OP AMP .

S .60

LM 380 - 2W AUDIO AMP. . . .

S .95

LM 377 - 2W Stereo Audio Amp.

S2.50

LM 381 - STEREO PREAMP. ..

SI .50

LM 382 - DUAL AUDIO PREAMP

SI .50

LM 311 - HI PER. COMPARATOR

S .90

LM 319 — Dual Hi Speed Comp. . ,

, SI .25

LM 339 - QUAD COMPARATOR

SI. 50

TRIACS SCR’S ;

<)>

SOLID STATE SALES

P.O. BOX 74A

SOMERVILLE, MASS. 02143 TEL (617) 547-4005

WE SHIP OVER 95%
OF OUR ORDERS THE
DAY WE RECEIVE THEM

134

CIRCLE NO. 59 ON FREE INFORMATION CARD

POPULAR ELECTRONICS

Popular Electronics

DECEMBER 1976
ADVERTISERS INDEX

READER

SERVICE NO. ADVERTISER PAGE NO.

1 A P Products, Inc. _ _ 96

2 AVR Electronics _ 112

Acoustic Fiber Sound Systems, Inc. _ 5

3 Adva Electronics _ 135

4 Advanced Microcomputer Products _ 118

6 Allison Automotive _ _ _ 96

7 Altaj Electronics _ 123

8 American Surplus Trading _ _112

9 Ancrona Corp. _ 133

10 Aries Inc. _ _118

11 Associated Electronics _ 93

Audio-Technica U.S., Inc. _ 47

13 B-K Product of Dynascan _ 22, 98

14 Bullet Electronics _ 134

15 Byte _ 1 _ 97

CREI Capitol Radio Engineering
Institute - 82,83,84,85

16 C&S Marketing _ 108

Circuit Design, Inc. _ 115

Cleveland Institute of

Electronics, Inc. _ 100, 101. 102, 103

17 Cobra, Product of Dynascan _ SECOND COVER

18 Continental Specialties Corporation _ 29

19 Continental Specialties Corporation _ 110

20 Delta Electronics Co. _ 132

21 Delta Products, Inc. _ 43

22 Deltagraph _ ___ 89

23 Digi-Key Corporation _ 117

24 Discwasher Group _ i

Dynaco, Inc. - 110

25 EICO _ 77

26 Edlle Electronics _ 122

27 Edmund Scientific Co. _ 136

28 Edsyn, Inc. _ 93

29 Eltron _ _ 128

30 Empire Scientific Corp. _ 79

31 Fluke _ 31

32 Godbout Electronics, Bill _ _126

34 Grantham School of Engineering _ 111

35 Handic U.S.A. Inc. _ _ _ 80

36 Hewlett-Packard - 10, 11

IMS Associates, Inc. _ 13

lasts, Inc. _ 112

37 Illinois Audio _ 112

38 International Electronics Unlimited - 130

39 JBL _ 21

40 James _ 124,125

41 James _ 131

33 Johnson Co., E. F _ FOURTH COVER

42 Leader Instrument Corp. _ - _ 113

43 McIntosh Laboratory Inc. _ 109

76 MITS _ 2

49 MITS _ 6,7

77 MITS _ 107

44 Mallory Distributor Products Co. - 35

NRI Schools _ 16, 17, 18, 19

National Technical Schools _ 87

45 New-Tone Electronics _ 126

46 OK Machines & Tool Corporation - 20

47 Olson Electronics _ 128

48 Optoelectronics _ 127

75 PAIA - 113

50 Phase Linear Corporation _ 106

51 Poly Paks _ 121

52 Polymorphic Systems _ 50

Processor Technology Co. - 73

53 Quest Electronics _ 116

54 RCA Electronic Instruments - 104, 105

Radio Shack _ 23

55 SBE Inc. _ 9

56 S. D. Sales Co _ 129

57 Sencore _ 94, 95

58 Shure Brothers Inc. - 81

59 Solid State Sales _ 134

60 Sound Guard _ 68

61 Southwest Technical Products Corporation — 67

Speaker Labs _ 97

63 Stanton Magnetics, Inc. _ THIRD COVER

64 Stereo Corporation of America 97

65 Stereo Discounters _ -109

74 Tec West U.S.A. _ 132

66 Technics by Panasonic _ * _ _ 25

72 Telex _ — - — 44

68 Vernitron Corporation — - - - - — 88

69 Wahl Clipper Corporation _ 113

70 Wawasee Electronics - - 91

71 Weller-Xcelite, Inc. _ — 8

67 Yamaha _ 27

CLASSIFIED ADVERTISING

116, 118, 122, 126, 130, 132, 134, 135

HOME ENTERTAINMENT FILMS

SHOP EARLY THE CONVENIENT WAY — BY MAIL ...
buy Sportlite Films for Christmas: Almost Unlimited Choice
— the NFL Super Bowl 1967 thru Super Bowl X — each a
separate Super 0 B&W or Color film. B&W, $8.95, Color,
$19.95 ea + $0.75 ea for shipping & handling. Or, order
400' Super 0 Color Mag Sound Films of Super Bowl IX & X;
or 75 World Series; or 1975 Stanley Cup Playoffs for $49.95
each POSTPAID. Other choices include: Armour Golf (6
asstd), Standard or Super 8 B&W 200’ reels, $7.95 ea; or
Indy “500" Standard 8 Color — 67, 8 & 9 at a closeout
price of only $14.95 ea PPD. Still puzzled? Send $1.00 for
new Columbia & Castle (Universal) catalogs & Sportlite
forms. Or call (312) 328-8955. Limited Offer — treat yourself
or a friend. SPORTLITE, Elect 12-X, 20 N. Wacker,
Chicago, IL 60606.

INVENTIONS WANTED

INVENTORS: Manufacturers Need New Products. Free
“Recommended Procedure," by a creative fee-based
invention service company. Washington Inventors Service,
422-T Washington Building, Washington, D. C. 20005.

RECOGNITION. ..FINANCIAL

REWARD.

"INVENTING I

CREDIT

If you have an idea for a new product, or a way
to make an old product better, contact us,"the

I idea people" We'll develop your idea, introduce it to
industry, negotiate for cash sale or royalty licensing.
Write now without cost or obligation for free

■ information. Fees are charged only for contracted
services. So send for your FREE "Inventor’s Kit." It
has important Marketing Information, a special
“Invention Record Form "and a Directory of 500
■ Corporations Seeking New Products.

%t1|l||i RAYMOND LEE ORGANIZATION

theV^ ± ; 230 Park Avenue North.New York, NY 10017
: At no cost or obligation, please rush my

FREE “Inventor's Kit No. A-112 »

DO-IT-YOURSELF

MODULAR TELEPHONES now available. Sets and com¬
ponents, compatible with Western Electric concept. Cata-
log 50 cents. Box 1654W, Costa Mesa, California 92626.
ORGANS — PA SYSTEMS, Electronic Pianos — String
Synthesizers — Speakers — Guitar Amplifiers — Electron¬
ic Sound Rotators. Modern integrated circuitry. Factory
assembled or easy-to-build custom kits. Send one dollar
(refunded with first purchase) to: WERSI Electronics, Dept.

D, Box 5318, Lancaster. PA 17601. _

U-BUILD Power Tools, Engraving Machine, Lathes, Profit¬
able Projects. Poor Man's Catalog 50 cents. Box 23-PE, i
Highland, Maryland 20777.

MUSICAL INSTRUMENTS

UP TO 60% DISCOUNT. Name brand instruments catalog.
Freeport Music, 114 G. Mahan St., W. Babylon, N.Y, 11704.
30% to 60% DISCOUNT! Any model: Guitar, Amp, Drums.
Free Catalog! Warehouse, PE-6, Box 11449, Ft. Worth,

Texas 76109. _

ORGANS — PA SYSTEMS, Electronic Pianos — String
Synthesizers — Speakers — Guitar Amplifiers — Electron¬
ic Sound Rotators. Modern integrated circuitry. Factory as¬
sembled or easy-to-build custom kits. Send one dollar (re¬
funded with first purchase) to: WERSI Electronics. Dept. D,
Box 5318, Lancaster, PA 17601.

RUBBER STAMPS

RUBBER ADDRESS STAMPS. Free Catalog. 45 type styles.
Jackson’s, Dept. K, Brownsville Rd., Mt. Vernon, 111. 62864.

FREE

DIODES
ZENERS &
RECTIFIERS

1*458 S/S1

1N<83 to

1*486 tm

1*746 to
1*759

1*914* 1S/S1

1*962 lo

1*974 4/51

1*3064 fi/Sl

1*3600 6/11

1*4001* 12/SI

1*4002 11/St

1*4003 12/SI

1*4004 12/SI

1*4005 10/SI

1*4006 1 0/SI

1*4007 10/SI

1*4148 1 S/SI

1*4154* 25/SI

1*4370 to
1*4372 2/51

1*4454 1 5/SI

1*4728 to
1*4753 3,51

1*5231 lo
1*5236 4/11

VARACTORS

INSIKto
1*6144 c

D5144UKI SS

F 7 43 2*1 Hi si

MVI30IO
UVI32 11

MV 1 820 to „

UV1B34 11

MV1I86 to „

MV1I72 R

MV2201 lo „

MV2206 n

TRANSISTORS
2N706 SO -24

2N7I8 .24

2N720 48

2*918 3/SI

2NI613 S0.29

2*1711 29

2*1890 .38

2N1893 38

2N22I9 .24

2*2222 6/SI

2N2222A* S/SI

2*2369 5/SI

2 *2606 to „

2*2609 **

2*2905 S0.24

2N2906A 24

2*2907* S/SI

2N3553 $1.50

2*3563 6/SI

2N3564 4/SI

2N356Sto
2N3588 6/S1

2*3638 6/SI

2M3638 A 5/tl

2*3641 5/SI

2N3642 S/SI

2*3643 6/SI

2N3644 4/SI

2N3646 4/SI

2*3688 to
2*3690 3/51

2*3691 to
2*3694 ,'51

2*3821 SO. 80

2*3822 .70

2N3823 .40

2*3866 .75

2*3903 (0*

2 *3906 8/51

2N39tB S5.00

2*3922 5.00

2*3954 3.20

2*3951 1.15

2*3970 1.00

TRANSISTORS

2N4091 3/SI

2*4122 3/51

2*4124 5/SI

2N424B 5/SI

2N4249 5/SI

2*4250 4/51

2*4274 5/SI

2N4302 SO -29

2*4303 .29

2 *4338 SI

2N4360M 2/SI

2*4391 SI

2N4392 S0.90

2*4416 2/SI

2M4416A SO .80

2*4856 to „

2*4861 M

2 *48 67 E 2/SI

2K4BE8E 2/SI

2*4881 S2-50

2*4181 SI

2N4965 3/SI

2N50B7 4/SI

2N5088 4/SI

2*5126(0
2N5135 B/S1

2*5131 5/SI

2*5139 5/St

2N5163 3/SI

2*5197 SSJW

2*5199 2.50

2*5210 3/SI

2* 5308 2/SI

2N5397 S1.50

2*5432 1.90

2*5457 3/SI

2*5458 S0J8

2*54*4 3/SI

2N5486 2/SI

2* 5543 S3. 00

2*5544 2.50

2N5561 1200

1C or FETVWITH
$5& $10 ORDERS. t
DATA SHEETS
WITH MANY ITEMS.
TRANSISTORS LINEAR IC's
2N5638 2/SI LM340K6 SI. 75

2N5640 2/SI LM340T-5 1.75

CP643 $4.00 LM340T6 1.75

CP650* $5.00 LM340T-12 1.75

CP651 S4.00 LM340T15 1.75

El 00 4/SI LM340T-24 1.75

ElOt 3/SI LM376N* .55

E102 3/SI LM377N 2.50

El 75 3/SI LM3I0N 1.29

MPF1Q2 to* NE5SSV* 2/SI

MPF104 3/S1 NE55CA S090

MPF112 4/SI LM709CH 29

MPS6515 3/SI LM709CN 29

SEI001 4/SI LM723H 2/SI

SE1002 4/SI LM723N* 3/SI

SE2001 4/SI LM739N St.OO

SE2002 4/SI LM741CK 3/SI

SE5001 to LM741CN* 4/SI

SE5003 3/51 LM741CN14 34

SE5020 13.00 LM747CM .65

T1S73 lo 748CJ DIP .35

TIS75 74JCJOIP 1.00

0IGITAL IC'S 8lS"m*["P U5

MM5738N S2J5 '•*»

SN7400N 16 LM1458N* 3/SI

SN7410N 16 LM2,,,N S»-4“

SN7420N .16 *fl25“CP

SN7440N .16 f”0.0* ??

SN745IN .18 £32"

SN7473N 26 , f

SN7475N .48 'f

SN7476N 25 \\

SN7490N 44 LU3BMN -55

5*7490* .44 RM)M£J 150

LINEAR IC'S RC4I94TK* 2.50

IM100H S7.S0 RC419SON* 125
LM301AN .27 RC4I95TK* 225
LM307H 27 LM42SOC* 2.00
LM308N 88 RC45SION .55
LM309K 125 N5556V .95

LM311N .90 N555BV .50
LM320KS 135 MA7805UC 1.25
LM320X12 135 8031 DIP* 3.75
LM320K I5 135 OM75492 89

♦SUPER SPECIALS:

20/S1

MPF102 200MHz RF Amp

3/SI

15/S1

40673 MOSFET RF Amp

SI .75

25/51

LM324 Quad 741 Op Amp

.94

4/S1

LM376Poi Volt Reg mOIP

.56

6/SI

NE555 Timer mOIP

2/SI

6/S1

LM723 2-37V Reg DIP

3/SI

.69

LM741 Comp Op Amp mDIP

4/SI

6/SI

LM1458 Oual 741 mDIP

3/SI

6/$1

CA3086 5 Trent Array DIP

.55

RC4195DN ±15V/50mA mDIP 1.25

1N914 lOOV/IOmA Diode
1N4001 10OV/1A Reel.
1N4154 30V 1N914
BR1 60V V4A Bridge Rec
2N2222A NPN Transistor
2N2907 PNP Transistor
2N3055 Power Xiftor 10A
2N3904 NPN Amp/Sw /HOO
2N3906 PNP Amp/Sw *1100
CP650 Power FET MtAmp

RF391 RF Power Amp Transistor 10-25W 0 3-30MHx TO*3 S5.00

555X Timer Tju-lhr Different pinout from 555 (w/datft) 3/S1

RC4194TK Dual Tracking Regulator ±0.2 to 30V ® 200mA TO-60 S2.50

8038 Waveform Generator MIA Wave With Circuits & Data $3.75

ADVA KITS:

LOGIC PROBE KIT —Use with CMOS, TTL. DTL, RTL, HTL, HtNILand
most MOS IC's. Built-in protection against polarity rev* rut and overvoltage.
Draws only a few mA from circuit under lest. Dual LED readout. Complete
kit includes case and clip leads. $8.96

VARIABLE REGULATED POWER SUPPLY KIT -Continuously wh
able from 3 to over IS Volts. Short-circuit proof with electronic current lim¬
iting at 300 mA. Compact size and typical regulation of 0.1% make this a great
bench or lab power supply. $11.95

FIXED REGULATED POWER SUPPLY KITS -Short-circuit proof with
thermal current limiting. Compact size and typical regulation of 0.5% make
these ideal for most electronic projects. Available for 5V @ 500mA, 6V 9
500mA. 9V © 500mA. 12V 9 400mA. 15V 9 300mA. Specify voltage when
ordering. $8.96 *a.

These eaiy-to-estemble kits include all components, complete detailed instruc¬
tions and plated fiberglass PC boards. Power supply kits do not include case or
meters. Add $1 25 per kit for pottage and handling.

(MAIL NOW! FREE DATA SHEETS iuppJi*d with meny iwmi from (hit Kt FREE ON
REQUEST-741 Op Amp with every order ot $5 or more-749 Duel Op Amp Or two E100
FET't with every order o( $10 or more, port merited prior (o 12/31/76. One fre* item per order.
ORDER TODAY— All iterm tubject lo prior tele end price v ubjecT to dung* without notice.
All item* ire new wrplut pern- 100% funcnonelly lined.

WRITE FOR FREE CATALOG #76 offering over 350 lemiconductort carried in ttodt.
Send ISdnemp.

TERMS. Send check or money order IU3. fundi) with order. We pev In Oeu POiUO (o U.S.,
Ceneda end Mexico (excepi on kill). SI. 00 handling charge on Drdert under $10. Calif, mi-
dents add 6% ulei tu. Foregn orders add postage. COO or dm -add $1.00 tefvke Charge.

ADVA

m Wmm m electronics

BOX 4181 EE, WOODSIDE, CA 94062
Tel. (415) 851-0455

CIRCLE NO. 3 ON FREE INFORMATION CARO

TREASURE FINDERS

DISCOVER true treasure hunting with world-famous deep¬
detecting mineral/metal detectors from White’s! Locate
gold, silver, rings, coins, artifacts and more! Sold,
serviced, warehoused world wide. Priced from $79.50. Free
Catalog! White’s Electronics, Dept, PD6Z, 1011 Pleasant
Valley Rd., Sweet Home, OR 97386.

MISCELLANEOUS

WINEMAKERS: Free illustrated catalog yeasts, equipment.

Semplex, Box 12276P, Minneapolis, Minn. 55412. _

FREE! Consumer Service Division Catalog. Includes a wide
variety of products associated with the special interests of
readers of Ziff-Davis magazines — PSYCHOLOGY TODAY,
POPULAR PHOTOGRAPHY. STEREO REVIEW, POPULAR
ELECTRONICS, BOATING, FLYING, CAR & DRIVER, CY¬
CLE, SKIING. Send for YOUR free catalog today. Consumer
Service Div.: 595 Broadway, Dept. CL, N.Y., NY 10012.

DECEMBER 1976

135

LIVE IN THE WORLD
OF TOMORROW . . .TODAY!

And our FREE 164 PAGE CATALOG is packed with
exciting and unusual values in electronic, hobby
and science items — plus 4,500 finds for fun, study
or profit ... for every member of the family.

A BETTER LIFE

LONr 1 JrcS7,0N 0F MEMORABLE,

long-lasting gifts for all ages.

NEW! THE UNIQUE EDMUND

4W' NEWTONIAN
RICHEST FIELD
REFLECTOR
TELESCOPE

KNOW YOUR

ALPHA FROM THETA! ^

For greater relaxation, concentration, monitor
your Alpha/Theta brainwaves w/ audible or visible

signal on Biosone II. Has 3 feedback modes, out-
puts to monitor logic signal, filter sel. feedback, .

broad sensitivity control; other professional feats, of $200-up units. Easily oper¬
ated 4-lb. portable has total brainwave monitoring capability! 2 9v tr. batteries.

No. 1668 AV (9Vzx5Hx4y4") . $149.95 Ppd.

LOW COST STARTERS’ UNIT (PORTABLE)

No. 71,809 AV {4V2x2%x4V4'') . $55.00 Ppd.

Clearest, brightest, most spectacular wide angle views of moon, stars, comets,
galaxies ever — and portable! See heavenly wonders! Sets up in seconds
(precollimated, ready to use). Pop the eyepiece in, focus — and zing! 3y20 field of
view gives you more stars in a single view than any other type ’scope! Bright, crisp,
finely resolved images. For sky gazing and earth gazing! Take it anywhere (only 17",
10 lb.), easily use it over your shoulder, (has adjustable carrying strap), in your lap,
on a tripod; rotate the spherical baseonitsown mount for use on a table, car hood.
Top quality optical system featurs AW', f/4 parabolic primary mirror (Va wave, 17"
F.L.); std. 28mm Kellner eyepiece (15X). No other telescope like it. Great Christmas
gift — it’s even bright red!

No. 2001 AV . $129.95 Ppd.

Spcl. Introductory Price! Goes to $149.95 Dec. 25, 1976

MAIL COUPON FOR

GIANT FREE
CATALOG!

164 PAGES • MORE THAN

_ 1 UNUSUAL

- ■ ■ i BARGAINS

Completely new 19/7 edition. New items, categories, illustrations. Dozen.
o< electrical and electromagnetic parts, accessories. Enormous selection of
Astronomical Telescopes. Unique lighting and ecological items. Micro¬
scopes, Binoculars, Magnifiers, Magnets, Lenses, Prisms. Hard-to-get-
surplus bargoins. Ingenious scientific tools. 1000's of components.
EDMUND SCIENTIFIC CO.

300 Edtcorp Building, lerrington. N. i. 01007

Please rush Free Giant Catalog "AV”

EDMUND SCIENTIFIC CO.

How Many Stock No.

□please send giant - - -

FREE CATALOG "AV” -

Charge my □ American Exp. -

□ BankAmericard □ Master Chg. _ _ _

My Card No. Is

' Card Expiration Date _

30-DAY MONEY-BACK GUARANTEE. Name _

You must be satisfied or return Address

any purchase in 30 days for full

refund. City _

300 Edscorp Building, Barrington, N.J. 08007

Description (B09) 547*^88 Price Eech I Total

Add Sendee and Handling Charge $1.00

I endow - - -

□ chock □money order for TOTAL

Signature _

136

CIRCLE NO. 27 ON FREE INFORMATION CARO

POPULAR ELECTRONICS

WKLS, Atlanta, broadcasts
100% disc-to-air. That* s why it uses
Stanton's 681 series... exclusively.

CIRCLE NO. 63 ON REE INFORMATION CARD

Top notch broadcasters who capture a large share of the
listening audience, are critically aware of the necessity to
achieve a superior quality of sound. Station WKLS is just
such a station.

As Bob Helbush, chief engineer, states:. “We broadcast
100% disc-to-air except for some commercials. So, for
maximum quality sound and phase stability, we use the
Stanton 681 SE for on-the-air use. We consider it the ideal
answer for that application. And our program director uses
Stanton’s 681 Triple-E for auditioning new releases before
we air them”.

And Don Waterman, General Manager, added: “Today,
every station in the SJR Communications group ... all eight
of them, all in Major Markets . . . use Stanton 681 cartridges
on every turntable”.

There are good reasons for this vast acceptance. Stan¬
ton's 681 Calibration Series cartridges offer improved track¬

9cb Hplfcuflh, Chief En.3ir.eec, making a qyalily -poretroS ch&ck using a 681 cartridge.

ing at all frequencies. They achieve perfectly flat frequency
response to beyond 20 Kc. And the top-of-the-line, superb
681 Triple-E has an ultra miniaturized stylus assembly with
substantially less mass than previously, yet it possesses
even greater durability than had been thought possible
to achieve.

Each 681 Series cartridge is guaranteed to meet its
specifications within exacting limits and each one boasts
the most meaningful warranty. An individually calibrated
test result is packed with each unit. _

Whether your usage involves record¬
ing, broadcasting or home entertain¬
ment, your choice should be the choice
of the professionals ... the STANTON 681 .

Write today for further information to
Stanton Magnetics , Terminal Drive,

Plainview, N.Y. 11803.

sTaNron

*»

You’ve, got four hundred
miles or dotted white line '
stretched out in front of you.
And a couple of dozen tons
riding in back.

That’s why you keep the
automatic CB sitting at your
side. No hassle, no gadget
controls, just the crisp, clean
Johnson sound all day long.
Automatically.

J ohnson’s exc Lusive voice
tailored circuitry automati¬
cally drops off unwanted fre¬
quencies to give yon clear

reception. Our automatic
noise limiter keeps reception
clean and built-in gain
control prevents "blasting”
and "fading.11

Johnson’s unique elec¬
tronic speech compression
automatically selects and
compresses the clearest
voice frequencies to produce

uniform, high-level modula¬
tion and maximum transmit
range. All automatically.
When you hit the road,

fo with Johnson CB. We
ack every Johnson with a
full year parts and labor
warranty and walk-in ser¬
vice at more than 850 loca¬
tions. See a Johnson CB
dealer and take off on the
great American adventure.

§3 JOHNSON

\i\*M ®

E. F. JOHNSON COMPANY. WASECA. MINN. 56093
In Canada: A C. Stmmonds & Sons. Ltd.

JOHNSON CB. THE GREAT AMERICAN ADVENT!!]

CIRCLE NO. 33 ON FREE INFORMATION C*PD

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Texts

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "197612 Popular Electronics"

See other formats